diff --git a/api/.rubocop.yml b/api/.rubocop.yml
index 57f00774a0..cf9fa1020c 100644
--- a/api/.rubocop.yml
+++ b/api/.rubocop.yml
@@ -5,3 +5,21 @@ Naming/FileName:
     - "lib/opentelemetry-api.rb"
 Style/ExplicitBlockArgument:
   Enabled: false
+Lint/AmbiguousOperatorPrecedence:
+  Enabled: false
+Minitest/AssertPredicate:
+  Enabled: false
+Minitest/RefutePredicate:
+  Enabled: false
+Performance/MethodObjectAsBlock:
+  Enabled: false
+Style/BitwisePredicate:
+  Enabled: false
+Style/EmptyClassDefinition:
+  Enabled: false
+Style/HashConversion:
+  Enabled: false
+Style/NegatedIfElseCondition:
+  Enabled: false
+Style/OneClassPerFile:
+  Enabled: false
diff --git a/api/Gemfile b/api/Gemfile
index 20463b7eb2..c65a396f3f 100644
--- a/api/Gemfile
+++ b/api/Gemfile
@@ -12,7 +12,7 @@ group :test, :development do
   gem 'benchmark-ips', '~> 2.14.0'
   gem 'minitest', '~> 5.27.0'
   gem 'rake', '~> 13.3.0'
-  gem 'rubocop', '~> 1.75.0'
+  gem 'rubocop', '~> 1.86.0'
   gem 'rubocop-minitest', '~> 0.38.0'
   gem 'rubocop-performance', '~> 1.25.0'
   gem 'rubocop-rake', '~> 0.7.1'
diff --git a/api/benchmarks/context_bench.rb b/api/benchmarks/context_bench.rb
index 73d2e45461..7153c4e075 100644
--- a/api/benchmarks/context_bench.rb
+++ b/api/benchmarks/context_bench.rb
@@ -94,7 +94,7 @@ def set_value(key, value)
     FiberLocalVarContext.new(new_entries)
   end
 
-  def set_values(values) # rubocop:disable Naming/AccessorMethodName:
+  def set_values(values) # rubocop:disable Naming/AccessorMethodName
     FiberLocalVarContext.new(@entries.merge(values))
   end
 
@@ -188,7 +188,7 @@ def set_value(key, value)
     FiberAttributeContext.new(new_entries)
   end
 
-  def set_values(values) # rubocop:disable Naming/AccessorMethodName:
+  def set_values(values) # rubocop:disable Naming/AccessorMethodName
     FiberAttributeContext.new(@entries.merge(values))
   end
 
@@ -287,7 +287,7 @@ def set_value(key, value)
     LinkedListContext.new(new_entries)
   end
 
-  def set_values(values) # rubocop:disable Naming/AccessorMethodName:
+  def set_values(values) # rubocop:disable Naming/AccessorMethodName
     LinkedListContext.new(@entries.merge(values))
   end
 
@@ -379,7 +379,7 @@ def set_value(key, value)
     new_entries
   end
 
-  def set_values(values) # rubocop:disable Naming/AccessorMethodName:
+  def set_values(values) # rubocop:disable Naming/AccessorMethodName
     merge(values)
   end
 
@@ -472,7 +472,7 @@ def set_value(key, value)
     ArrayContext.new(new_entries)
   end
 
-  def set_values(values) # rubocop:disable Naming/AccessorMethodName:
+  def set_values(values) # rubocop:disable Naming/AccessorMethodName
     ArrayContext.new(@entries.merge(values))
   end
 
@@ -591,7 +591,7 @@ def set_value(key, value)
     FiberLocalArrayContext.new(new_entries)
   end
 
-  def set_values(values) # rubocop:disable Naming/AccessorMethodName:
+  def set_values(values) # rubocop:disable Naming/AccessorMethodName
     FiberLocalArrayContext.new(@entries.merge(values))
   end
 
@@ -684,7 +684,7 @@ def set_value(key, value)
     ImmutableArrayContext.new(new_entries)
   end
 
-  def set_values(values) # rubocop:disable Naming/AccessorMethodName:
+  def set_values(values) # rubocop:disable Naming/AccessorMethodName
     ImmutableArrayContext.new(@entries.merge(values))
   end
 
@@ -777,7 +777,7 @@ def set_value(key, value)
     FiberLocalImmutableArrayContext.new(new_entries)
   end
 
-  def set_values(values) # rubocop:disable Naming/AccessorMethodName:
+  def set_values(values) # rubocop:disable Naming/AccessorMethodName
     FiberLocalImmutableArrayContext.new(@entries.merge(values))
   end
 
diff --git a/api/lib/opentelemetry/baggage/propagation/text_map_propagator.rb b/api/lib/opentelemetry/baggage/propagation/text_map_propagator.rb
index 0197c2f9c3..fde67fff0f 100644
--- a/api/lib/opentelemetry/baggage/propagation/text_map_propagator.rb
+++ b/api/lib/opentelemetry/baggage/propagation/text_map_propagator.rb
@@ -99,7 +99,7 @@ def encode(baggage)
         end
 
         def encode_value(key, entry)
-          result = +"#{URI.encode_uri_component(key.to_s)}=#{URI.encode_uri_component(entry.value.to_s)}"
+          result = "#{URI.encode_uri_component(key.to_s)}=#{URI.encode_uri_component(entry.value.to_s)}"
           # We preserve metadata received on extract and assume it's already formatted
           # for transport. It's sent as-is without further processing.
           result << ";#{entry.metadata}" if entry.metadata
diff --git a/api/lib/opentelemetry/context.rb b/api/lib/opentelemetry/context.rb
index de4e2565b8..c118f1cd07 100644
--- a/api/lib/opentelemetry/context.rb
+++ b/api/lib/opentelemetry/context.rb
@@ -162,7 +162,7 @@ def set_value(key, value)
     #   entries.
     # @param [Object] value Object to be stored under key
     # @return [Context]
-    def set_values(values) # rubocop:disable Naming/AccessorMethodName:
+    def set_values(values) # rubocop:disable Naming/AccessorMethodName
       Context.new(@entries.merge(values))
     end
 
diff --git a/api/lib/opentelemetry/context/propagation/rack_env_getter.rb b/api/lib/opentelemetry/context/propagation/rack_env_getter.rb
index 27e83fd736..8b601dfc39 100644
--- a/api/lib/opentelemetry/context/propagation/rack_env_getter.rb
+++ b/api/lib/opentelemetry/context/propagation/rack_env_getter.rb
@@ -32,8 +32,7 @@ def keys(carrier)
         private
 
         def to_rack_key(key)
-          # Use + for mutable string interpolation in pre-Ruby 3.0.
-          ret = +"HTTP_#{key}"
+          ret = "HTTP_#{key}"
           ret.tr!('-', '_')
           ret.upcase!
           ret
diff --git a/api/lib/opentelemetry/trace/propagation/trace_context.rb b/api/lib/opentelemetry/trace/propagation/trace_context.rb
index 1030809896..ffff24ed7b 100644
--- a/api/lib/opentelemetry/trace/propagation/trace_context.rb
+++ b/api/lib/opentelemetry/trace/propagation/trace_context.rb
@@ -14,6 +14,7 @@ module Propagation
       # for context propagation in the W3C Trace Context format.
       module TraceContext
         extend self
+
         TEXT_MAP_PROPAGATOR = TextMapPropagator.new
 
         private_constant :TEXT_MAP_PROPAGATOR
diff --git a/api/lib/opentelemetry/trace/tracestate.rb b/api/lib/opentelemetry/trace/tracestate.rb
index c4718d4de7..8f206760d5 100644
--- a/api/lib/opentelemetry/trace/tracestate.rb
+++ b/api/lib/opentelemetry/trace/tracestate.rb
@@ -18,7 +18,7 @@ class << self
         # @param [String] header Encoding of the tracestate header defined by
         #   the W3C Trace Context specification https://www.w3.org/TR/trace-context/
         # @return [Tracestate] A new Tracestate instance or DEFAULT
-        def from_string(header) # rubocop:disable Metrics/CyclomaticComplexity:
+        def from_string(header) # rubocop:disable Metrics/CyclomaticComplexity
           return DEFAULT if header.nil? || header.empty?
 
           hash = header.split(',').each_with_object({}) do |member, memo|
diff --git a/api/test/opentelemetry/context_test.rb b/api/test/opentelemetry/context_test.rb
index db7ae8959e..5fc2fc45fb 100644
--- a/api/test/opentelemetry/context_test.rb
+++ b/api/test/opentelemetry/context_test.rb
@@ -302,7 +302,7 @@
             # Manipulate _this fiber's_ context stack.
             Context.attach(new_context)
           ensure
-            locals.each { |k, _| t2[k] = nil } # rubocop:disable Style/HashEachMethods (locals is not a Hash)
+            locals.each { |k, _| t2[k] = nil } # rubocop:disable Style/HashEachMethods --(locals is not a Hash)
           end.resume
         end
         _(log_stream.string).must_be_empty
@@ -348,7 +348,7 @@
             # Manipulate _this thread's_ context stack.
             Context.attach(new_context)
           ensure
-            locals.each { |k, _| t2[k] = nil } # rubocop:disable Style/HashEachMethods (locals is not a Hash)
+            locals.each { |k, _| t2[k] = nil } # rubocop:disable Style/HashEachMethods --(locals is not a Hash)
           end.join
         end
         _(log_stream.string).must_be_empty
diff --git a/api/test/opentelemetry/trace/trace_flags_test.rb b/api/test/opentelemetry/trace/trace_flags_test.rb
index d949a51d00..3d454fe248 100644
--- a/api/test/opentelemetry/trace/trace_flags_test.rb
+++ b/api/test/opentelemetry/trace/trace_flags_test.rb
@@ -5,7 +5,7 @@
 describe OpenTelemetry::Trace::TraceFlags do
   describe '.new' do
     it 'is private' do
-      _(-> { OpenTelemetry::Trace::TraceFlags.new(0) })\
+      _(-> { OpenTelemetry::Trace::TraceFlags.new(0) })
         .must_raise(NoMethodError)
     end
   end
diff --git a/api/test/opentelemetry/trace/tracestate_test.rb b/api/test/opentelemetry/trace/tracestate_test.rb
index 55108dd41a..d93b64f56d 100644
--- a/api/test/opentelemetry/trace/tracestate_test.rb
+++ b/api/test/opentelemetry/trace/tracestate_test.rb
@@ -5,7 +5,7 @@
 describe OpenTelemetry::Trace::Tracestate do
   describe '.new' do
     it 'is private' do
-      _(-> { OpenTelemetry::Trace::Tracestate.new({}) })\
+      _(-> { OpenTelemetry::Trace::Tracestate.new({}) })
         .must_raise(NoMethodError)
     end
   end
diff --git a/common/.rubocop.yml b/common/.rubocop.yml
index db98871e84..d2808b99b9 100644
--- a/common/.rubocop.yml
+++ b/common/.rubocop.yml
@@ -16,3 +16,11 @@ Metrics/BlockLength:
 Naming/FileName:
   Exclude:
     - "lib/opentelemetry-common.rb"
+Lint/AmbiguousRange:
+  Enabled: false
+Minitest/AssertPredicate:
+  Enabled: false
+Minitest/RefutePredicate:
+  Enabled: false
+Performance/MethodObjectAsBlock:
+  Enabled: false
diff --git a/common/lib/opentelemetry-common.rb b/common/lib/opentelemetry-common.rb
index 49ede56132..2cc8c10f8e 100644
--- a/common/lib/opentelemetry-common.rb
+++ b/common/lib/opentelemetry-common.rb
@@ -4,4 +4,4 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
-require_relative './opentelemetry/common'
+require_relative 'opentelemetry/common'
diff --git a/common/lib/opentelemetry/common/http.rb b/common/lib/opentelemetry/common/http.rb
index d68047c00c..ca1c5022c1 100644
--- a/common/lib/opentelemetry/common/http.rb
+++ b/common/lib/opentelemetry/common/http.rb
@@ -12,4 +12,4 @@ module HTTP
   end
 end
 
-require_relative './http/client_context'
+require_relative 'http/client_context'
diff --git a/common/lib/opentelemetry/common/propagation.rb b/common/lib/opentelemetry/common/propagation.rb
index 35d1d11c5d..eb0277b6c7 100644
--- a/common/lib/opentelemetry/common/propagation.rb
+++ b/common/lib/opentelemetry/common/propagation.rb
@@ -4,8 +4,8 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
-require_relative './propagation/rack_env_getter'
-require_relative './propagation/symbol_key_getter'
+require_relative 'propagation/rack_env_getter'
+require_relative 'propagation/symbol_key_getter'
 
 module OpenTelemetry
   module Common
diff --git a/common/lib/opentelemetry/common/propagation/rack_env_getter.rb b/common/lib/opentelemetry/common/propagation/rack_env_getter.rb
index d51d84c66a..7c97082e80 100644
--- a/common/lib/opentelemetry/common/propagation/rack_env_getter.rb
+++ b/common/lib/opentelemetry/common/propagation/rack_env_getter.rb
@@ -29,8 +29,7 @@ def keys(carrier)
         private
 
         def to_rack_key(key)
-          # Use + for mutable string interpolation in pre-Ruby 3.0.
-          ret = +"HTTP_#{key}"
+          ret = "HTTP_#{key}"
           ret.tr!('-', '_')
           ret.upcase!
           ret
diff --git a/common/lib/opentelemetry/common/utilities.rb b/common/lib/opentelemetry/common/utilities.rb
index 6b524656df..af8759a41a 100644
--- a/common/lib/opentelemetry/common/utilities.rb
+++ b/common/lib/opentelemetry/common/utilities.rb
@@ -164,4 +164,4 @@ def valid_exporter?(exporter)
   end
 end
 
-require_relative './http/client_context'
+require_relative 'http/client_context'
diff --git a/contrib/rubocop.yml b/contrib/rubocop.yml
index 15958fe9f4..4f2c884148 100644
--- a/contrib/rubocop.yml
+++ b/contrib/rubocop.yml
@@ -5,14 +5,16 @@ plugins:
   - rubocop-performance
 
 AllCops:
-  NewCops: disable
-  SuggestExtensions: false
+  NewCops: enable
+  SuggestExtensions: true
   TargetRubyVersion: "3.3"
   Exclude:
     - "vendor/**/*"
 
 Bundler/OrderedGems:
   Enabled: false
+Gemspec/DevelopmentDependencies:
+ Enabled: false
 
 Layout/LineLength:
   Enabled: false
@@ -20,6 +22,9 @@ Layout/LineLength:
 Lint/ConstantDefinitionInBlock:
   Exclude:
     - "test/**/*"
+Lint/EmptyBlock:
+  Exclude:
+    - "**/*test.rb"
 Lint/MissingSuper:
   Enabled: false
 Lint/UnusedMethodArgument:
@@ -36,6 +41,18 @@ Style/ModuleFunction:
   Enabled: false
 Style/NumericPredicate:
   Enabled: false
+Style/RedundantConstantBase:
+  Enabled: false
+Style/RedundantRegexpEscape:
+  Enabled: false
 Style/StringConcatenation:
   Exclude:
     - "test/**/*"
+
+Gemspec/RequireMFA:
+  # We probably want to figure out how to set this up for the organization
+  Enabled: false
+
+# we need to review the below
+Minitest/EmptyLineBeforeAssertionMethods:
+  Enabled: false
diff --git a/exporter/otlp-common/.rubocop.yml b/exporter/otlp-common/.rubocop.yml
index e4a5d6fa5f..fbef3cd1fa 100644
--- a/exporter/otlp-common/.rubocop.yml
+++ b/exporter/otlp-common/.rubocop.yml
@@ -15,3 +15,5 @@ Metrics/PerceivedComplexity:
 Naming/FileName:
   Exclude:
     - "lib/opentelemetry-exporter-otlp-common.rb"
+Style/ObjectThen:
+  Enabled: false
diff --git a/exporter/otlp-http/.rubocop.yml b/exporter/otlp-http/.rubocop.yml
index 4f07d8989f..5aefaedf29 100644
--- a/exporter/otlp-http/.rubocop.yml
+++ b/exporter/otlp-http/.rubocop.yml
@@ -12,3 +12,11 @@ Metrics/PerceivedComplexity:
 Naming/FileName:
   Exclude:
     - "lib/opentelemetry-exporter-otlp-http.rb"
+Lint/DuplicateBranch:
+  Enabled: false
+Lint/SuppressedExceptionInNumberConversion:
+  Enabled: false
+Performance/MapCompact:
+  Enabled: false
+Performance/MethodObjectAsBlock:
+  Enabled: false
diff --git a/exporter/otlp-logs/.rubocop.yml b/exporter/otlp-logs/.rubocop.yml
index 5c3cff545c..a101774638 100644
--- a/exporter/otlp-logs/.rubocop.yml
+++ b/exporter/otlp-logs/.rubocop.yml
@@ -17,3 +17,11 @@ Style/FrozenStringLiteralComment:
     - gemfiles/**/*
 Metrics/BlockLength:
   Enabled: false
+Lint/DuplicateBranch:
+  Enabled: false
+Lint/SuppressedExceptionInNumberConversion:
+  Enabled: false
+Performance/MapCompact:
+  Enabled: false
+Performance/MethodObjectAsBlock:
+ Enabled: false
diff --git a/exporter/otlp-metrics/.rubocop.yml b/exporter/otlp-metrics/.rubocop.yml
index 52c76f71be..9af1f3804c 100644
--- a/exporter/otlp-metrics/.rubocop.yml
+++ b/exporter/otlp-metrics/.rubocop.yml
@@ -29,3 +29,11 @@ Metrics/BlockLength:
 Naming/FileName:
   Exclude:
     - "lib/opentelemetry-exporter-otlp-metrics.rb"
+Lint/DuplicateBranch:
+  Enabled: false
+Lint/SuppressedExceptionInNumberConversion:
+  Enabled: false
+Performance/MapCompact:
+  Enabled: false
+Performance/MethodObjectAsBlock:
+  Enabled: false
diff --git a/exporter/otlp-metrics/lib/opentelemetry/exporter/otlp/metrics/metrics_exporter.rb b/exporter/otlp-metrics/lib/opentelemetry/exporter/otlp/metrics/metrics_exporter.rb
index 9157e1fdfe..7b488f767d 100644
--- a/exporter/otlp-metrics/lib/opentelemetry/exporter/otlp/metrics/metrics_exporter.rb
+++ b/exporter/otlp-metrics/lib/opentelemetry/exporter/otlp/metrics/metrics_exporter.rb
@@ -19,7 +19,7 @@
 require 'opentelemetry/metrics'
 require 'opentelemetry/sdk/metrics'
 
-require_relative './util'
+require_relative 'util'
 
 module OpenTelemetry
   module Exporter
diff --git a/exporter/otlp/.rubocop.yml b/exporter/otlp/.rubocop.yml
index 8206eb72b1..2d820d1ec1 100644
--- a/exporter/otlp/.rubocop.yml
+++ b/exporter/otlp/.rubocop.yml
@@ -21,3 +21,13 @@ Metrics/BlockLength:
 Naming/FileName:
   Exclude:
     - "lib/opentelemetry-exporter-otlp.rb"
+Lint/DuplicateBranch:
+  Enabled: false
+Lint/SuppressedExceptionInNumberConversion:
+  Enabled: false
+Performance/MapCompact:
+  Enabled: false
+Performance/MethodObjectAsBlock:
+  Enabled: false
+Style/ObjectThen:
+  Enabled: false
diff --git a/exporter/otlp/lib/opentelemetry/exporter/otlp/exporter.rb b/exporter/otlp/lib/opentelemetry/exporter/otlp/exporter.rb
index 9647177f61..30655f901a 100644
--- a/exporter/otlp/lib/opentelemetry/exporter/otlp/exporter.rb
+++ b/exporter/otlp/lib/opentelemetry/exporter/otlp/exporter.rb
@@ -418,7 +418,7 @@ def as_otlp_any_value(value)
         end
 
         def prepare_endpoint(endpoint)
-          endpoint ||= ENV['OTEL_EXPORTER_OTLP_TRACES_ENDPOINT']
+          endpoint ||= ENV.fetch('OTEL_EXPORTER_OTLP_TRACES_ENDPOINT', nil)
           if endpoint.nil?
             endpoint = ENV['OTEL_EXPORTER_OTLP_ENDPOINT'] || 'http://localhost:4318'
             endpoint += '/' unless endpoint.end_with?('/')
diff --git a/exporter/zipkin/.rubocop.yml b/exporter/zipkin/.rubocop.yml
index 6cb190171d..391fc7d3c7 100644
--- a/exporter/zipkin/.rubocop.yml
+++ b/exporter/zipkin/.rubocop.yml
@@ -20,3 +20,9 @@ Naming/FileName:
     - "lib/opentelemetry-exporter-zipkin.rb"
 Style/ExplicitBlockArgument:
   Enabled: false
+Lint/AmbiguousOperatorPrecedence:
+  Enabled: false
+Lint/SuppressedExceptionInNumberConversion:
+  Enabled: false
+Minitest/SkipEnsure:
+  Enabled: false
diff --git a/exporter/zipkin/test/test_helper.rb b/exporter/zipkin/test/test_helper.rb
index 1e5a4a5152..9d760d051d 100644
--- a/exporter/zipkin/test/test_helper.rb
+++ b/exporter/zipkin/test/test_helper.rb
@@ -42,6 +42,7 @@ def create_span_data(status: nil, kind: nil, attributes: nil, total_recorded_att
 # Test helper for Zipkin Exporter
 class InMemoryMetricsReporter
   include OpenTelemetry::SDK::Trace::Export::MetricsReporter
+
   attr_reader :counters, :records, :observes
 
   def initialize
diff --git a/logs_api/.rubocop.yml b/logs_api/.rubocop.yml
index 28ba0fcc75..53fdb4b20f 100644
--- a/logs_api/.rubocop.yml
+++ b/logs_api/.rubocop.yml
@@ -10,3 +10,7 @@ Metrics/CyclomaticComplexity:
 Naming/FileName:
   Exclude:
     - "lib/opentelemetry-logs-api.rb"
+Lint/EmptyClass:
+  Enabled: false
+Style/ReduceToHash:
+  Enabled: false
diff --git a/logs_api/Gemfile b/logs_api/Gemfile
index 79ff8feb51..d1a0063cbb 100644
--- a/logs_api/Gemfile
+++ b/logs_api/Gemfile
@@ -13,7 +13,7 @@ group :test, :development do
   gem 'logger', '~> 1.7.0' # should move to appraisals
   gem 'minitest', '~> 5.27.0'
   gem 'rake', '~> 13.3.0'
-  gem 'rubocop', '~> 1.75.0'
+  gem 'rubocop', '~> 1.86.0'
   gem 'rubocop-minitest', '~> 0.38.0'
   gem 'rubocop-performance', '~> 1.25.0'
   gem 'rubocop-rake', '~> 0.7.1'
diff --git a/metrics_api/.rubocop.yml b/metrics_api/.rubocop.yml
index c7539fe342..d8f77bb0b2 100644
--- a/metrics_api/.rubocop.yml
+++ b/metrics_api/.rubocop.yml
@@ -11,3 +11,7 @@ Metrics/CyclomaticComplexity:
 Naming/FileName:
   Exclude:
     - "lib/opentelemetry-metrics-api.rb"
+Minitest/AssertKindOf:
+  Enabled: false
+Style/EmptyClassDefinition:
+  Enabled: false
diff --git a/metrics_api/Gemfile b/metrics_api/Gemfile
index 71f599ebd9..9740ff19b8 100644
--- a/metrics_api/Gemfile
+++ b/metrics_api/Gemfile
@@ -12,7 +12,7 @@ group :test, :development do
   gem 'benchmark-ips', '~> 2.14.0'
   gem 'minitest', '~> 5.27.0'
   gem 'rake', '~> 13.3.0'
-  gem 'rubocop', '~> 1.75.0'
+  gem 'rubocop', '~> 1.86.0'
   gem 'rubocop-minitest', '~> 0.38.0'
   gem 'rubocop-performance', '~> 1.25.0'
   gem 'rubocop-rake', '~> 0.7.1'
diff --git a/metrics_sdk/.rubocop.yml b/metrics_sdk/.rubocop.yml
index 3c6f491adc..b43862aad6 100644
--- a/metrics_sdk/.rubocop.yml
+++ b/metrics_sdk/.rubocop.yml
@@ -11,3 +11,29 @@ Metrics/CyclomaticComplexity:
 Naming/FileName:
   Exclude:
     - "lib/opentelemetry-metrics-sdk.rb"
+Lint/AmbiguousOperatorPrecedence:
+  Enabled: false
+Lint/AmbiguousRange:
+  Enabled: false
+Naming/BlockForwarding:
+  Enabled: false
+Naming/PredicateMethod:
+  Enabled: false
+Performance/CollectionLiteralInLoop:
+  Enabled: false
+Style/ArgumentsForwarding:
+  Enabled: false
+Style/CollectionQuerying:
+  Enabled: false
+Style/EmptyClassDefinition:
+  Enabled: false
+Style/FetchEnvVar:
+  Enabled: false
+Style/MapIntoArray:
+  Enabled: false
+Style/NilLambda:
+  Enabled: false
+Style/SuperArguments:
+  Enabled: false
+Lint/SymbolConversion:
+  Enabled: false
diff --git a/metrics_sdk/Gemfile b/metrics_sdk/Gemfile
index d2b9bd2a4c..677c913ef0 100644
--- a/metrics_sdk/Gemfile
+++ b/metrics_sdk/Gemfile
@@ -11,7 +11,7 @@ gemspec
 group :test, :development do
   gem 'minitest', '~> 5.27.0'
   gem 'rake', '~> 13.3.0'
-  gem 'rubocop', '~> 1.75.0'
+  gem 'rubocop', '~> 1.86.0'
   gem 'rubocop-minitest', '~> 0.38.0'
   gem 'rubocop-performance', '~> 1.25.0'
   gem 'rubocop-rake', '~> 0.7.1'
diff --git a/propagator/b3/lib/opentelemetry-propagator-b3.rb b/propagator/b3/lib/opentelemetry-propagator-b3.rb
index 5180d87832..85997ee49b 100644
--- a/propagator/b3/lib/opentelemetry-propagator-b3.rb
+++ b/propagator/b3/lib/opentelemetry-propagator-b3.rb
@@ -5,4 +5,4 @@
 # SPDX-License-Identifier: Apache-2.0
 
 require 'opentelemetry-api'
-require_relative './opentelemetry/propagator/b3'
+require_relative 'opentelemetry/propagator/b3'
diff --git a/propagator/b3/lib/opentelemetry/propagator/b3.rb b/propagator/b3/lib/opentelemetry/propagator/b3.rb
index 1032b14bd2..b3327c3292 100644
--- a/propagator/b3/lib/opentelemetry/propagator/b3.rb
+++ b/propagator/b3/lib/opentelemetry/propagator/b3.rb
@@ -35,7 +35,7 @@ def debug?(context)
   end
 end
 
-require_relative './b3/version'
-require_relative './b3/text_map_extractor'
-require_relative './b3/multi'
-require_relative './b3/single'
+require_relative 'b3/version'
+require_relative 'b3/text_map_extractor'
+require_relative 'b3/multi'
+require_relative 'b3/single'
diff --git a/propagator/b3/lib/opentelemetry/propagator/b3/multi.rb b/propagator/b3/lib/opentelemetry/propagator/b3/multi.rb
index 5d3af9be8c..2bfe4eb13c 100644
--- a/propagator/b3/lib/opentelemetry/propagator/b3/multi.rb
+++ b/propagator/b3/lib/opentelemetry/propagator/b3/multi.rb
@@ -4,7 +4,7 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
-require_relative './multi/text_map_propagator'
+require_relative 'multi/text_map_propagator'
 
 # OpenTelemetry is an open source observability framework, providing a
 # general-purpose API, SDK, and related tools required for the instrumentation
diff --git a/propagator/b3/lib/opentelemetry/propagator/b3/single.rb b/propagator/b3/lib/opentelemetry/propagator/b3/single.rb
index f53ceb63ba..4ca2eb0b98 100644
--- a/propagator/b3/lib/opentelemetry/propagator/b3/single.rb
+++ b/propagator/b3/lib/opentelemetry/propagator/b3/single.rb
@@ -4,7 +4,7 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
-require_relative './single/text_map_propagator'
+require_relative 'single/text_map_propagator'
 
 # OpenTelemetry is an open source observability framework, providing a
 # general-purpose API, SDK, and related tools required for the instrumentation
diff --git a/propagator/jaeger/.rubocop.yml b/propagator/jaeger/.rubocop.yml
index 8d589790b2..5081253fe9 100644
--- a/propagator/jaeger/.rubocop.yml
+++ b/propagator/jaeger/.rubocop.yml
@@ -9,3 +9,13 @@ Metrics/BlockLength:
 Naming/FileName:
   Exclude:
     - 'lib/opentelemetry-propagator-jaeger.rb'
+
+Performance/RedundantSplitRegexpArgument:
+  Enabled: false
+
+Style/BitwisePredicate:
+  Enabled: false
+Style/NegatedIfElseCondition:
+  Enabled: false
+Style/RedundantRegexpArgument:
+  Enabled: false
diff --git a/propagator/jaeger/lib/opentelemetry-propagator-jaeger.rb b/propagator/jaeger/lib/opentelemetry-propagator-jaeger.rb
index b7647f672d..bcf95dad80 100644
--- a/propagator/jaeger/lib/opentelemetry-propagator-jaeger.rb
+++ b/propagator/jaeger/lib/opentelemetry-propagator-jaeger.rb
@@ -5,4 +5,4 @@
 # SPDX-License-Identifier: Apache-2.0
 
 require 'opentelemetry-api'
-require_relative './opentelemetry/propagator/jaeger'
+require_relative 'opentelemetry/propagator/jaeger'
diff --git a/propagator/jaeger/lib/opentelemetry/propagator/jaeger.rb b/propagator/jaeger/lib/opentelemetry/propagator/jaeger.rb
index c3bd020eb0..8b0583e4aa 100644
--- a/propagator/jaeger/lib/opentelemetry/propagator/jaeger.rb
+++ b/propagator/jaeger/lib/opentelemetry/propagator/jaeger.rb
@@ -4,7 +4,7 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
-require_relative './jaeger/text_map_propagator'
+require_relative 'jaeger/text_map_propagator'
 
 # OpenTelemetry is an open source observability framework, providing a
 # general-purpose API, SDK, and related tools required for the instrumentation
diff --git a/propagator/jaeger/test/text_map_propagator_test.rb b/propagator/jaeger/test/text_map_propagator_test.rb
index d070f46191..984de6cc68 100644
--- a/propagator/jaeger/test/text_map_propagator_test.rb
+++ b/propagator/jaeger/test/text_map_propagator_test.rb
@@ -265,8 +265,7 @@ def create_context(trace_id:,
     it 'injects to rack keys' do
       rack_env_setter = Object.new
       def rack_env_setter.set(carrier, key, value)
-        # Use + for mutable string interpolation in pre-Ruby 3.0.
-        rack_key = +"HTTP_#{key}"
+        rack_key = "HTTP_#{key}"
         rack_key.tr!('-', '_')
         rack_key.upcase!
         carrier[rack_key] = value
diff --git a/registry/lib/opentelemetry-registry.rb b/registry/lib/opentelemetry-registry.rb
index 8efeff3e95..915096c5fc 100644
--- a/registry/lib/opentelemetry-registry.rb
+++ b/registry/lib/opentelemetry-registry.rb
@@ -5,4 +5,4 @@
 # SPDX-License-Identifier: Apache-2.0
 
 require 'opentelemetry'
-require_relative './opentelemetry/instrumentation'
+require_relative 'opentelemetry/instrumentation'
diff --git a/registry/lib/opentelemetry/instrumentation.rb b/registry/lib/opentelemetry/instrumentation.rb
index d87aa8426c..1c58129fad 100644
--- a/registry/lib/opentelemetry/instrumentation.rb
+++ b/registry/lib/opentelemetry/instrumentation.rb
@@ -10,12 +10,13 @@
 #
 # The OpenTelemetry module provides global accessors for telemetry objects.
 # See the documentation for the `opentelemetry-api` gem for details.
-require_relative './instrumentation/registry'
+require_relative 'instrumentation/registry'
 
 module OpenTelemetry
   # Instrumentation should be able to handle the case when the library is not installed on a user's system.
   module Instrumentation
     extend self
+
     # @return [Registry] registry containing all known
     #  instrumentation
     def registry
diff --git a/registry/lib/opentelemetry/instrumentation/registry.rb b/registry/lib/opentelemetry/instrumentation/registry.rb
index 4fa21526bd..3bde5b1ea3 100644
--- a/registry/lib/opentelemetry/instrumentation/registry.rb
+++ b/registry/lib/opentelemetry/instrumentation/registry.rb
@@ -89,4 +89,4 @@ def install_instrumentation(instrumentation, config)
   end
 end
 
-require_relative './registry/version'
+require_relative 'registry/version'
diff --git a/sdk/.rubocop.yml b/sdk/.rubocop.yml
index d37dda60aa..3d887be965 100644
--- a/sdk/.rubocop.yml
+++ b/sdk/.rubocop.yml
@@ -8,3 +8,23 @@ Naming/FileName:
 
 Style/ExplicitBlockArgument:
   Enabled: false
+Lint/AmbiguousOperatorPrecedence:
+  Enabled: false
+Lint/EmptyClass:
+  Enabled: false
+Minitest/UselessAssertion:
+  Enabled: false
+Naming/BlockForwarding:
+  Enabled: false
+Naming/PredicateMethod:
+  Enabled: false
+Style/ArgumentsForwarding:
+  Enabled: false
+Style/EmptyClassDefinition:
+  Enabled: false
+Style/HashConversion:
+  Enabled: false
+Style/NegatedIfElseCondition:
+  Enabled: false
+Style/PredicateWithKind:
+  Enabled: false
diff --git a/sdk/Gemfile b/sdk/Gemfile
index 383e2b6c56..8624a951bb 100644
--- a/sdk/Gemfile
+++ b/sdk/Gemfile
@@ -12,7 +12,7 @@ group :test, :development do
   gem 'opentelemetry-instrumentation-base', '~> 0.26.0'
   gem 'minitest', '~> 5.27.0'
   gem 'rake', '~> 13.3.0'
-  gem 'rubocop', '~> 1.75.0'
+  gem 'rubocop', '~> 1.86.0'
   gem 'rubocop-minitest', '~> 0.38.0'
   gem 'rubocop-performance', '~> 1.25.0'
   gem 'rubocop-rake', '~> 0.7.1'
diff --git a/sdk/lib/opentelemetry/sdk/resources/resource.rb b/sdk/lib/opentelemetry/sdk/resources/resource.rb
index 4a96256944..53e55c5354 100644
--- a/sdk/lib/opentelemetry/sdk/resources/resource.rb
+++ b/sdk/lib/opentelemetry/sdk/resources/resource.rb
@@ -41,7 +41,7 @@ def telemetry_sdk
               SemanticConventions::Resource::TELEMETRY_SDK_VERSION => OpenTelemetry::SDK::VERSION
             }
 
-            resource_pairs = ENV['OTEL_RESOURCE_ATTRIBUTES']
+            resource_pairs = ENV.fetch('OTEL_RESOURCE_ATTRIBUTES', nil)
             return create(resource_attributes) unless resource_pairs.is_a?(String)
 
             resource_pairs.split(',').each do |pair|
@@ -68,7 +68,7 @@ def process
           private
 
           def service_name_from_env
-            service_name = ENV['OTEL_SERVICE_NAME']
+            service_name = ENV.fetch('OTEL_SERVICE_NAME', nil)
             create(SemanticConventions::Resource::SERVICE_NAME => service_name) unless service_name.nil?
           end
         end
diff --git a/sdk/lib/opentelemetry/sdk/trace/export/batch_span_processor.rb b/sdk/lib/opentelemetry/sdk/trace/export/batch_span_processor.rb
index ce79c832b6..c689ea1bae 100644
--- a/sdk/lib/opentelemetry/sdk/trace/export/batch_span_processor.rb
+++ b/sdk/lib/opentelemetry/sdk/trace/export/batch_span_processor.rb
@@ -49,7 +49,7 @@ def initialize(exporter,
                          schedule_delay: Float(ENV.fetch('OTEL_BSP_SCHEDULE_DELAY', 5_000)),
                          max_queue_size: Integer(ENV.fetch('OTEL_BSP_MAX_QUEUE_SIZE', 2048)),
                          max_export_batch_size: Integer(ENV.fetch('OTEL_BSP_MAX_EXPORT_BATCH_SIZE', 512)),
-                         start_thread_on_boot: String(ENV['OTEL_RUBY_BSP_START_THREAD_ON_BOOT']) !~ /false/i,
+                         start_thread_on_boot: String(ENV.fetch('OTEL_RUBY_BSP_START_THREAD_ON_BOOT', nil)) !~ /false/i,
                          metrics_reporter: nil)
             raise ArgumentError if max_export_batch_size > max_queue_size
             raise ArgumentError, "exporter #{exporter.inspect} does not appear to be a valid exporter" unless Common::Utilities.valid_exporter?(exporter)
diff --git a/sdk/lib/opentelemetry/sdk/trace/tracer_provider.rb b/sdk/lib/opentelemetry/sdk/trace/tracer_provider.rb
index 3569451635..d1689a9d45 100644
--- a/sdk/lib/opentelemetry/sdk/trace/tracer_provider.rb
+++ b/sdk/lib/opentelemetry/sdk/trace/tracer_provider.rb
@@ -170,7 +170,7 @@ def internal_start_span(name, kind, attributes, links, start_timestamp, parent_c
         private
 
         def sampler_from_environment(default_sampler)
-          case ENV['OTEL_TRACES_SAMPLER']
+          case ENV.fetch('OTEL_TRACES_SAMPLER', nil)
           when 'always_on' then Samplers::ALWAYS_ON
           when 'always_off' then Samplers::ALWAYS_OFF
           when 'traceidratio' then Samplers.trace_id_ratio_based(Float(ENV.fetch('OTEL_TRACES_SAMPLER_ARG', 1.0)))
diff --git a/sdk_experimental/.rubocop.yml b/sdk_experimental/.rubocop.yml
index 31998db8e6..f1dbb83455 100644
--- a/sdk_experimental/.rubocop.yml
+++ b/sdk_experimental/.rubocop.yml
@@ -14,3 +14,11 @@ Naming/FileName:
     - "lib/opentelemetry-sdk-experimental.rb"
 Naming/MethodParameterName:
   Enabled: false
+Lint/AmbiguousOperatorPrecedence:
+  Enabled: false
+Lint/DuplicateBranch:
+  Enabled: false
+Naming/PredicateMethod:
+  Enabled: false
+Style/NegatedIfElseCondition:
+  Enabled: false
diff --git a/sdk_experimental/Gemfile b/sdk_experimental/Gemfile
index 8cfc44c34a..0e982bf0b8 100644
--- a/sdk_experimental/Gemfile
+++ b/sdk_experimental/Gemfile
@@ -11,7 +11,7 @@ gemspec
 group :test, :development do
   gem 'minitest', '~> 5.27.0'
   gem 'rake', '~> 13.3.0'
-  gem 'rubocop', '~> 1.75.0'
+  gem 'rubocop', '~> 1.86.0'
   gem 'rubocop-minitest', '~> 0.38.0'
   gem 'rubocop-performance', '~> 1.25.0'
   gem 'rubocop-rake', '~> 0.7.1'
diff --git a/test_helpers/lib/opentelemetry/test_helpers.rb b/test_helpers/lib/opentelemetry/test_helpers.rb
index ab65f3581f..eed2094689 100644
--- a/test_helpers/lib/opentelemetry/test_helpers.rb
+++ b/test_helpers/lib/opentelemetry/test_helpers.rb
@@ -11,6 +11,7 @@ module OpenTelemetry
   # OpenTelemetry Ruby gems.
   module TestHelpers
     extend self
+
     NULL_LOGGER = Logger.new(File::NULL)
 
     # reset_opentelemetry is a test helper used to clear