diff --git a/Library/Homebrew/rubocops/shared/desc_helper.rb b/Library/Homebrew/rubocops/shared/desc_helper.rb
index 63cc95537c..5e1e273c51 100644
--- a/Library/Homebrew/rubocops/shared/desc_helper.rb
+++ b/Library/Homebrew/rubocops/shared/desc_helper.rb
@@ -64,6 +64,10 @@ module RuboCop
         name_regex = name.delete("-").split("").join('[\s\-]?')
         problem "Description shouldn't start with the #{type} name." if regex_match_group(desc, /^#{name_regex}\b/i)
 
+        if type == :cask && match = regex_match_group(desc, /\b(macOS|Mac( ?OS( ?X)?)?|OS ?X)\b/i)
+          problem "Description shouldn't contain the platform." unless match[1] == "MAC"
+        end
+
         # Check if a full stop is used at the end of a desc (apart from in the case of "etc.").
         if regex_match_group(desc, /\.$/) && !string_content(desc).end_with?("etc.")
           problem "Description shouldn't end with a full stop."
diff --git a/Library/Homebrew/test/rubocops/cask/desc_spec.rb b/Library/Homebrew/test/rubocops/cask/desc_spec.rb
index 38793ccf99..8b06c40a12 100644
--- a/Library/Homebrew/test/rubocops/cask/desc_spec.rb
+++ b/Library/Homebrew/test/rubocops/cask/desc_spec.rb
@@ -63,4 +63,40 @@ describe RuboCop::Cop::Cask::Desc do
       end
     RUBY
   end
+
+  it "does not contain the platform" do
+    expect_offense <<~RUBY, "/homebrew-cask/Casks/foo.rb"
+      cask 'foo-bar' do
+        desc 'macOS status bar monitor'
+              ^^^^^ Description shouldn\'t contain the platform.
+      end
+    RUBY
+
+    expect_offense <<~RUBY, "/homebrew-cask/Casks/foo.rb"
+      cask 'foo-bar' do
+        desc 'Toggles dark mode on Mac OS Mojave'
+                                   ^^^^^^ Description shouldn\'t contain the platform.
+      end
+    RUBY
+
+    expect_offense <<~RUBY, "/homebrew-cask/Casks/foo.rb"
+      cask 'foo-bar' do
+        desc 'Better input source switcher for OS X'
+                                               ^^^^ Description shouldn\'t contain the platform.
+      end
+    RUBY
+
+    expect_offense <<~RUBY, "/homebrew-cask/Casks/foo.rb"
+      cask 'foo-bar' do
+        desc 'Media Manager for Mac OS X'
+                                ^^^^^^^^ Description shouldn\'t contain the platform.
+      end
+    RUBY
+
+    expect_no_offenses <<~RUBY
+      cask 'foo' do
+        desc 'MAC address changer'
+      end
+    RUBY
+  end
 end