Apple - Is there a Google Calendar Mac Desktop App?

Yes, the built-in Calendar app lets you add them.

For your Mac:

1. On your computer, open Calendar
2. In the top left corner of your screen, click Calendar > Preferences.
3. Click the Accounts tab. On the left side of the Accounts tab, click +.
4. Select Google > Continue.
5. Enter your Gmail address, password, and verification code (if you have one).
6. Click Accept.
7. On the Accounts tab, choose how often you want Apple Calendar and Google Calendar to sync.

For more information, see https://support.google.com/calendar/answer/99358

Here's another way, adding Google Calendar as a Chrome App with standalone window. The calendar is then available in Launchpad and the Dock.

1. Navigate Chrome to your calendar URL, e.g https://calendar.google.com
2. Create Chrome App shortcut from the URL - Chrome drop down menu > More Tools > Create Shortcut

Note: check the "Open as window" box

3. Open the "Google Calendar" from Chrome Apps or Launchpad!

4. Select "Keep in Dock" to keep the calendar icon in the MacOS Dock (optional)

That's it! Your Google Calendar App is now available as a standalone window app from the MacOS Dock and Launchpad.

I find the design of Apple's Calendar app frustrating on a number of levels, and also prefer not to have to context switch between the Google Calendar web UI and something else.

To solve this, I'm using Fluid, which wraps any URL in a native shell.

This lets me use all the features of the familiar Google Calendar while avoiding the problem of having my calendar constantly getting lost amongst my browser tabs.