diff --git a/changelog/new_style_redundant_interpolation_unfreeze.md b/changelog/new_style_redundant_interpolation_unfreeze.md
new file mode 100644
index 000000000000..19624fb8501e
--- /dev/null
+++ b/changelog/new_style_redundant_interpolation_unfreeze.md
@@ -0,0 +1 @@
+* [#13061](https://github.com/rubocop/rubocop/issues/13061): Add new `Style/RedundantInterpolationUnfreeze` cop to check for `dup` and `@+` on interpolated strings in Ruby >= 3.0. ([@earlopain][])
diff --git a/config/default.yml b/config/default.yml
index bc52d408ecf7..9233144ef20d 100644
--- a/config/default.yml
+++ b/config/default.yml
@@ -5057,6 +5057,11 @@ Style/RedundantInterpolation:
   VersionAdded: '0.76'
   VersionChanged: '1.30'
 
+Style/RedundantInterpolationUnfreeze:
+  Description: 'Checks for redundant unfreezing of interpolated strings.'
+  Enabled: pending
+  VersionAdded: '<<next>>'
+
 Style/RedundantLineContinuation:
   Description: 'Check for redundant line continuation.'
   Enabled: pending
diff --git a/lib/rubocop.rb b/lib/rubocop.rb
index f8f7fbcbcd76..9140b6eaf7bd 100644
--- a/lib/rubocop.rb
+++ b/lib/rubocop.rb
@@ -583,6 +583,7 @@
 require_relative 'rubocop/cop/style/redundant_filter_chain'
 require_relative 'rubocop/cop/style/redundant_heredoc_delimiter_quotes'
 require_relative 'rubocop/cop/style/redundant_initialize'
+require_relative 'rubocop/cop/style/redundant_interpolation_unfreeze'
 require_relative 'rubocop/cop/style/redundant_line_continuation'
 require_relative 'rubocop/cop/style/redundant_regexp_argument'
 require_relative 'rubocop/cop/style/redundant_regexp_constructor'
diff --git a/lib/rubocop/cop/mixin/frozen_string_literal.rb b/lib/rubocop/cop/mixin/frozen_string_literal.rb
index d32e196af8bc..315880708bd6 100644
--- a/lib/rubocop/cop/mixin/frozen_string_literal.rb
+++ b/lib/rubocop/cop/mixin/frozen_string_literal.rb
@@ -20,7 +20,7 @@ def frozen_string_literal_comment_exists?
 
       def frozen_string_literal?(node)
         frozen_string = if target_ruby_version >= 3.0
-                          uninterpolated_string?(node) || frozen_heredoc?(node)
+                          uninterpolated_string?(node) || uninterpolated_heredoc?(node)
                         else
                           FROZEN_STRING_LITERAL_TYPES_RUBY27.include?(node.type)
                         end
@@ -32,11 +32,12 @@ def uninterpolated_string?(node)
         node.str_type? || (node.dstr_type? && node.each_descendant(:begin).none?)
       end
 
-      def frozen_heredoc?(node)
+      def uninterpolated_heredoc?(node)
         return false unless node.dstr_type? && node.heredoc?
 
         node.children.all?(&:str_type?)
       end
+      alias frozen_heredoc? uninterpolated_heredoc?
 
       def frozen_string_literals_enabled?
         ruby_version = processed_source.ruby_version
diff --git a/lib/rubocop/cop/style/redundant_interpolation_unfreeze.rb b/lib/rubocop/cop/style/redundant_interpolation_unfreeze.rb
new file mode 100644
index 000000000000..0765c1a20044
--- /dev/null
+++ b/lib/rubocop/cop/style/redundant_interpolation_unfreeze.rb
@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+module RuboCop
+  module Cop
+    module Style
+      # Before Ruby 3.0, interpolated strings followed the frozen string literal
+      # magic comment which sometimes made it necessary to explicitly unfreeze them.
+      # Ruby 3.0 changed interpolated strings to always be unfrozen which makes
+      # unfreezing them redundant.
+      #
+      # @example
+      #   # bad
+      #   +"#{foo} bar"
+      #
+      #   # bad
+      #   "#{foo} bar".dup
+      #
+      #   # good
+      #  "#{foo} bar"
+      #
+      class RedundantInterpolationUnfreeze < Base
+        include FrozenStringLiteral
+        extend AutoCorrector
+        extend TargetRubyVersion
+
+        MSG = "Don't unfreeze interpolated strings as they are already unfrozen."
+
+        RESTRICT_ON_SEND = %i[+@ dup].freeze
+
+        minimum_target_ruby_version 3.0
+
+        def on_send(node)
+          return if node.arguments?
+          return unless (receiver = node.receiver)
+          return unless receiver.dstr_type?
+          return if uninterpolated_string?(receiver) || uninterpolated_heredoc?(receiver)
+
+          add_offense(node.loc.selector) do |corrector|
+            corrector.remove(node.loc.selector)
+            corrector.remove(node.loc.dot) unless node.unary_operation?
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/spec/rubocop/cop/style/redundant_interpolation_unfreeze_spec.rb b/spec/rubocop/cop/style/redundant_interpolation_unfreeze_spec.rb
new file mode 100644
index 000000000000..918d886a7149
--- /dev/null
+++ b/spec/rubocop/cop/style/redundant_interpolation_unfreeze_spec.rb
@@ -0,0 +1,118 @@
+# frozen_string_literal: true
+
+RSpec.describe RuboCop::Cop::Style::RedundantInterpolationUnfreeze, :config do
+  context 'target_ruby_version >= 3.0', :ruby30 do
+    it 'registers an offense for `@+`' do
+      expect_offense(<<~'RUBY')
+        +"#{foo} bar"
+        ^ Don't unfreeze interpolated strings as they are already unfrozen.
+      RUBY
+
+      expect_correction(<<~'RUBY')
+        "#{foo} bar"
+      RUBY
+    end
+
+    it 'registers an offense for `@+` as a normal method call' do
+      expect_offense(<<~'RUBY')
+        "#{foo} bar".+@
+                     ^^ Don't unfreeze interpolated strings as they are already unfrozen.
+      RUBY
+
+      expect_correction(<<~'RUBY')
+        "#{foo} bar"
+      RUBY
+    end
+
+    it 'registers an offense for `dup`' do
+      expect_offense(<<~'RUBY')
+        "#{foo} bar".dup
+                     ^^^ Don't unfreeze interpolated strings as they are already unfrozen.
+      RUBY
+
+      expect_correction(<<~'RUBY')
+        "#{foo} bar"
+      RUBY
+    end
+
+    it 'registers an offense for interpolated heredoc with `@+`' do
+      expect_offense(<<~'RUBY')
+        foo(+<<~MSG)
+            ^ Don't unfreeze interpolated strings as they are already unfrozen.
+          foo #{bar}
+          baz
+        MSG
+      RUBY
+
+      expect_correction(<<~'RUBY')
+        foo(<<~MSG)
+          foo #{bar}
+          baz
+        MSG
+      RUBY
+    end
+
+    it 'registers an offense for interpolated heredoc with `dup`' do
+      expect_offense(<<~'RUBY')
+        foo(<<~MSG.dup)
+                   ^^^ Don't unfreeze interpolated strings as they are already unfrozen.
+          foo #{bar}
+          baz
+        MSG
+      RUBY
+
+      expect_correction(<<~'RUBY')
+        foo(<<~MSG)
+          foo #{bar}
+          baz
+        MSG
+      RUBY
+    end
+
+    it 'registers no offense for uninterpolated heredoc' do
+      expect_no_offenses(<<~'RUBY')
+        foo(+<<~'MSG')
+          foo #{bar}
+          baz
+        MSG
+      RUBY
+    end
+
+    it 'registers no offense for plain string literals' do
+      expect_no_offenses(<<~RUBY)
+        "foo".dup
+      RUBY
+    end
+
+    it 'registers no offense for other types' do
+      expect_no_offenses(<<~RUBY)
+        local.dup
+      RUBY
+    end
+
+    it 'registers no offense when the method has arguments' do
+      expect_no_offenses(<<~'RUBY')
+        "#{foo} bar".dup(baz)
+      RUBY
+    end
+
+    it 'registers no offense for multiline string literals' do
+      expect_no_offenses(<<~RUBY)
+        +'foo' \
+        'bar'
+      RUBY
+    end
+
+    it 'registers no offense when there is no receiver' do
+      expect_no_offenses(<<~RUBY)
+        dup
+      RUBY
+    end
+  end
+
+  context 'target_ruby_version < 3.0', :ruby27, unsupported_on: :prism do
+    it 'accepts unfreezing an interpolated string' do
+      expect_no_offenses('+"#{foo} bar"')
+    end
+  end
+end