diff --git a/Library/Homebrew/cask/cmd/install.rb b/Library/Homebrew/cask/cmd/install.rb
index 1a3cd870db..961662f7a7 100644
--- a/Library/Homebrew/cask/cmd/install.rb
+++ b/Library/Homebrew/cask/cmd/install.rb
@@ -2,6 +2,7 @@
 # frozen_string_literal: true
 
 require "cask_dependent"
+require "extend/os/cask/cmd/install"
 
 module Cask
   class Cmd
@@ -68,8 +69,6 @@ module Cask
         zap: nil,
         dry_run: nil
       )
-        # TODO: Refactor and move to extend/os
-        odie "Installing casks is supported only on macOS" unless OS.mac? # rubocop:disable Homebrew/MoveToExtendOS
 
         options = {
           verbose:        verbose,
diff --git a/Library/Homebrew/extend/os/cask/cmd/install.rb b/Library/Homebrew/extend/os/cask/cmd/install.rb
new file mode 100644
index 0000000000..aeb209fac6
--- /dev/null
+++ b/Library/Homebrew/extend/os/cask/cmd/install.rb
@@ -0,0 +1,4 @@
+# typed: strict
+# frozen_string_literal: true
+
+require "extend/os/linux/cask/cmd/install" if OS.linux?
diff --git a/Library/Homebrew/extend/os/linux/cask/cmd/install.rb b/Library/Homebrew/extend/os/linux/cask/cmd/install.rb
new file mode 100644
index 0000000000..201666f52a
--- /dev/null
+++ b/Library/Homebrew/extend/os/linux/cask/cmd/install.rb
@@ -0,0 +1,29 @@
+# typed: false
+# frozen_string_literal: true
+
+require "cask_dependent"
+
+module Cask
+  class Cmd
+    # Cask implementation of the `brew install` command.
+    #
+    # @api private
+    class Install < AbstractCommand
+      def self.install_casks(
+        _casks,
+        verbose: nil,
+        force: nil,
+        adopt: nil,
+        binaries: nil,
+        skip_cask_deps: nil,
+        require_sha: nil,
+        quarantine: nil,
+        quiet: nil,
+        zap: nil,
+        dry_run: nil
+      )
+        odie "Installing casks is supported only on macOS"
+      end
+    end
+  end
+end