diff --git a/CHANGELOG.md b/CHANGELOG.md
index d6c9e308eb15..63313ab0891f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5350,3 +5350,4 @@
 [@agargiulo]: https://github.com/agargiulo
 [@muirdm]: https://github.com/muirdm
 [@noon-ng]: https://github.com/noon-ng
+[@ohbarye]: https://github.com/ohbarye
diff --git a/changelog/fix_faulty_calculation_in_uncommunicative_name.md b/changelog/fix_faulty_calculation_in_uncommunicative_name.md
new file mode 100644
index 000000000000..af556b002fb9
--- /dev/null
+++ b/changelog/fix_faulty_calculation_in_uncommunicative_name.md
@@ -0,0 +1 @@
+* [#8229](https://github.com/rubocop-hq/rubocop/issues/8229): Fix faulty calculation in UncommunicativeName. ([@ohbarye][])
diff --git a/lib/rubocop/cop/mixin/uncommunicative_name.rb b/lib/rubocop/cop/mixin/uncommunicative_name.rb
index 20db9ae6d675..83ebca232788 100644
--- a/lib/rubocop/cop/mixin/uncommunicative_name.rb
+++ b/lib/rubocop/cop/mixin/uncommunicative_name.rb
@@ -24,7 +24,11 @@ def check(node, args)
           name = full_name.gsub(/\A(_+)/, '')
           next if allowed_names.include?(name)
 
-          range = arg_range(arg, name.size)
+          length = full_name.size
+          length += 1 if arg.restarg_type?
+          length += 2 if arg.kwrestarg_type?
+
+          range = arg_range(arg, length)
           issue_offenses(node, range, name)
         end
       end
diff --git a/spec/rubocop/cop/naming/block_parameter_name_spec.rb b/spec/rubocop/cop/naming/block_parameter_name_spec.rb
index c2da63c39a3c..44beff8c80b7 100644
--- a/spec/rubocop/cop/naming/block_parameter_name_spec.rb
+++ b/spec/rubocop/cop/naming/block_parameter_name_spec.rb
@@ -44,6 +44,18 @@
     RUBY
   end
 
+  it 'registers offense when param with prefix is less than minimum length' do
+    expect_offense(<<~RUBY)
+      something do |_a, __b, *c, **__d|
+                    ^^ Block parameter must be at least 2 characters long.
+                        ^^^ Block parameter must be at least 2 characters long.
+                             ^^ Block parameter must be at least 2 characters long.
+                                 ^^^^^ Block parameter must be at least 2 characters long.
+        do_stuff
+      end
+    RUBY
+  end
+
   it 'registers offense when param contains uppercase characters' do
     expect_offense(<<~RUBY)
       something { |number_One| do_stuff }
diff --git a/spec/rubocop/cop/naming/method_parameter_name_spec.rb b/spec/rubocop/cop/naming/method_parameter_name_spec.rb
index d675094a9fd9..647d610fde40 100644
--- a/spec/rubocop/cop/naming/method_parameter_name_spec.rb
+++ b/spec/rubocop/cop/naming/method_parameter_name_spec.rb
@@ -99,6 +99,18 @@ def something(ab)
     RUBY
   end
 
+  it 'registers offense when parameter with prefix is less than minimum length' do
+    expect_offense(<<~RUBY)
+      def something(_a, __b, *c, **__d)
+                    ^^ Method parameter must be at least 3 characters long.
+                        ^^^ Method parameter must be at least 3 characters long.
+                             ^^ Method parameter must be at least 3 characters long.
+                                 ^^^^^ Method parameter must be at least 3 characters long.
+        do_stuff
+      end
+    RUBY
+  end
+
   it 'registers offense when parameter contains uppercase characters' do
     expect_offense(<<~RUBY)
       def something(number_One)