diff --git a/Library/Homebrew/test/cask/installer_spec.rb b/Library/Homebrew/test/cask/installer_spec.rb
index f205bd7074..e9da105157 100644
--- a/Library/Homebrew/test/cask/installer_spec.rb
+++ b/Library/Homebrew/test/cask/installer_spec.rb
@@ -16,7 +16,7 @@ describe Cask::Installer, :cask do
       expect(caffeine.config.appdir.join("Caffeine.app")).to be_a_directory
     end
 
-    it "works with dmg-based Casks" do
+    it "works with HFS+ dmg-based Casks" do
       asset = Cask::CaskLoader.load(cask_path("container-dmg"))
 
       described_class.new(asset).install
@@ -25,6 +25,24 @@ describe Cask::Installer, :cask do
       expect(asset.config.appdir.join("container")).to be_a_file
     end
 
+    it "works with APFS dmg-based Casks" do
+      asset = Cask::CaskLoader.load(cask_path("container-apfs-dmg"))
+      diskutil_list_command = "diskutil list | grep '/dev'"
+
+      sleep 5
+      original_diskutil_list = `#{diskutil_list_command}`
+
+      described_class.new(asset).install
+
+      expect(Cask::Caskroom.path.join("container-apfs-dmg", asset.version)).to be_a_directory
+      expect(asset.config.appdir.join("container")).to be_a_file
+
+      sleep 5
+      expect { system diskutil_list_command }
+        .to output(original_diskutil_list)
+        .to_stdout_from_any_process
+    end
+
     it "works with tar-gz-based Casks" do
       asset = Cask::CaskLoader.load(cask_path("container-tar-gz"))
 
diff --git a/Library/Homebrew/test/support/fixtures/cask/Casks/container-apfs-dmg.rb b/Library/Homebrew/test/support/fixtures/cask/Casks/container-apfs-dmg.rb
new file mode 100644
index 0000000000..6fc863207b
--- /dev/null
+++ b/Library/Homebrew/test/support/fixtures/cask/Casks/container-apfs-dmg.rb
@@ -0,0 +1,9 @@
+cask "container-apfs-dmg" do
+  version "1.2.3"
+  sha256 "0630aa1145e8c3fa77aeb6ec414fee35204e90f224d6d06cb23e18a4d6112a5d"
+
+  url "file://#{TEST_FIXTURE_DIR}/cask/container-apfs.dmg"
+  homepage "https://brew.sh/container-apfs-dmg"
+
+  app "container"
+end
diff --git a/Library/Homebrew/test/support/fixtures/cask/container-apfs.dmg b/Library/Homebrew/test/support/fixtures/cask/container-apfs.dmg
new file mode 100644
index 0000000000..5ddbd80772
Binary files /dev/null and b/Library/Homebrew/test/support/fixtures/cask/container-apfs.dmg differ
diff --git a/Library/Homebrew/unpack_strategy/dmg.rb b/Library/Homebrew/unpack_strategy/dmg.rb
index 5f2fea6825..f758c1a78c 100644
--- a/Library/Homebrew/unpack_strategy/dmg.rb
+++ b/Library/Homebrew/unpack_strategy/dmg.rb
@@ -87,10 +87,27 @@ module UnpackStrategy
         return unless path.exist?
 
         if tries > 1
-          system_command! "diskutil",
-                          args:         ["eject", path],
-                          print_stderr: false,
-                          verbose:      verbose
+          disk_info = system_command!(
+            "diskutil",
+            args:         ["info", "-plist", path],
+            print_stderr: false,
+            verbose:      verbose,
+          )
+
+          # For HFS, just use <mount-path>
+          # For APFS, find the <physical-store> corresponding to <mount-path>
+          eject_paths = disk_info.plist
+                                 .fetch("APFSPhysicalStores", [])
+                                 .map { |store| store["APFSPhysicalStore"] }
+                                 .compact
+                                 .presence || [path]
+
+          eject_paths.each do |eject_path|
+            system_command! "diskutil",
+                            args:         ["eject", eject_path],
+                            print_stderr: false,
+                            verbose:      verbose
+          end
         else
           system_command! "diskutil",
                           args:         ["unmount", "force", path],