diff --git a/Library/Homebrew/cmd/untap.rb b/Library/Homebrew/cmd/untap.rb
index 04e1f86d863fa..8d485311cb6f5 100644
--- a/Library/Homebrew/cmd/untap.rb
+++ b/Library/Homebrew/cmd/untap.rb
@@ -136,7 +136,7 @@ def installed_casks_for(tap:)
             next
           end
 
-          cask if cask.installed?
+          cask if cask.installed? && cask.tab.tap == tap
         end
       end
 
diff --git a/Library/Homebrew/test/cmd/untap_spec.rb b/Library/Homebrew/test/cmd/untap_spec.rb
index 030ab9c4e6880..e4beffbbd8d92 100644
--- a/Library/Homebrew/test/cmd/untap_spec.rb
+++ b/Library/Homebrew/test/cmd/untap_spec.rb
@@ -249,7 +249,7 @@ class InvalidSpec < Formula
 
   describe "#installed_casks_for", :cask do
     shared_examples "finds installed casks in tap", :no_api do
-      def load_cask(token:, with_cask_file: false, mock_install: false, deprecated: false)
+      def load_cask(token:, with_cask_file: false, mock_install: false, deprecated: false, tap: subject)
         cask_source = <<~RUBY
           cask '#{token}' do
             version "1.2.3"
@@ -269,10 +269,10 @@ def load_cask(token:, with_cask_file: false, mock_install: false, deprecated: fa
 
         return if deprecated
 
-        cask_loader = Cask::CaskLoader::FromContentLoader.new(cask_source, tap: subject)
+        cask_loader = Cask::CaskLoader::FromContentLoader.new(cask_source, tap:)
         cask = cask_loader.load(config: nil)
 
-        InstallHelper.install_with_caskfile(cask) if mock_install
+        InstallHelper.stub_cask_installation(cask) if mock_install
 
         cask
       end
@@ -295,6 +295,19 @@ def load_cask(token:, with_cask_file: false, mock_install: false, deprecated: fa
       it "returns the expected casks" do
         expect(described_class.new(%w[arg1]).installed_casks_for(tap: subject)).to eq([currently_installed_cask])
       end
+
+      it "excludes casks installed from another tap" do
+        load_cask(token: "other_tap_install", with_cask_file: true, mock_install: true,
+                  tap: subject.core_cask_tap? ? Tap.fetch("homebrew", "bar") : CoreCaskTap.instance)
+
+        expect(described_class.new(%w[arg1]).installed_casks_for(tap: subject)).to eq([currently_installed_cask])
+      end
+
+      it "includes installed casks without a receipt" do
+        (currently_installed_cask.metadata_main_container_path/AbstractTab::FILENAME).unlink
+
+        expect(described_class.new(%w[arg1]).installed_casks_for(tap: subject)).to eq([currently_installed_cask])
+      end
     end
 
     context "with core cask tap" do