diff --git a/.rubocop.yml b/.rubocop.yml
index f959c48..7d1b26f 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -24,6 +24,9 @@ InternalAffairs/UndefinedConfig:
 
 Naming/InclusiveLanguage:
   FlaggedTerms:
+    behaviour:
+      Suggestions:
+        - behavior
     offence:
       Suggestions:
         - offense
diff --git a/docs/modules/ROOT/pages/cops_performance.adoc b/docs/modules/ROOT/pages/cops_performance.adoc
index 5cb55b8..59baffb 100644
--- a/docs/modules/ROOT/pages/cops_performance.adoc
+++ b/docs/modules/ROOT/pages/cops_performance.adoc
@@ -1268,7 +1268,7 @@ is wanted.
 === Safety
 
 This cop is unsafe because `Range#include?` (or `Range#member?`) and `Range#cover?`
-are not equivalent behaviour.
+are not equivalent behavior.
 
 === Examples
 
diff --git a/legacy-docs/cops_performance.md b/legacy-docs/cops_performance.md
index e6e4181..307ad89 100644
--- a/legacy-docs/cops_performance.md
+++ b/legacy-docs/cops_performance.md
@@ -607,7 +607,7 @@ end points of the `Range`. In a great majority of cases, this is what
 is wanted.
 
 This cop is `Safe: false` by default because `Range#include?` and
-`Range#cover?` are not equivalent behaviour.
+`Range#cover?` are not equivalent behavior.
 
 ### Examples
 
diff --git a/lib/rubocop/cop/performance/range_include.rb b/lib/rubocop/cop/performance/range_include.rb
index 8308ac3..8658c81 100644
--- a/lib/rubocop/cop/performance/range_include.rb
+++ b/lib/rubocop/cop/performance/range_include.rb
@@ -11,7 +11,7 @@ module Performance
       #
       # @safety
       #   This cop is unsafe because `Range#include?` (or `Range#member?`) and `Range#cover?`
-      #   are not equivalent behaviour.
+      #   are not equivalent behavior.
       #
       # @example
       #   # bad