Poco

This plugin installs a widget for showing a Google Calendar agenda on the sidebar. 
Once installed it adds a sidebar widget called ‘Google Calendar’ that may be dragged into your sidebar. 
Each widget can be configured with a ID of the calendar feed, a title, and the number of agenda items to show.
The calendar feed ID is the ID next to ‘Calendar ID:’ in the Google Calendar settings.
Multiple widgets can be used on the same page and each one can reference a different feed.
See also <a href="http://notions.okuda.ca/wordpress-plugins/google-calendar-widget/" rel="nofollow ugc">http://notions.okuda.ca/wordpress-plugins/google-calendar-widget/</a>

Google Calendar Widget

This plugin installs a sidebar widget that can show the upcoming events from a Google Calendar feed.

michielve

If you update to version 20230111, please note that:
<ul>
<li>The theming has slightly been changed. Now there is distinction between bundled and custom themes.</li>
<li>The previously bundled dark and light themes have been renamed. So if you used these themes, you now have to manually update these themes to the new pgc-dark and pgc-light themes.</li>
<li>The popup theme has been removed. This can now be set in your custom theme.</li>
</ul>
See for details about this release: https://blog.michielvaneerd.nl/wordpress-plugins/private-google-calendars/version-20230111-details/
This plugin can display multiple private and public Google calendars with a shortcode, Gutenberg block or as a widget.
See the <a href="https://blog.michielvaneerd.nl/wordpress-plugins/private-google-calendars/" rel="nofollow ugc">webpage</a> for more information.
<h4>Features</h4>
<ul>
<li>Access to private (and public) calendars by using OAuth2 or an API key.</li>
<li>Adjustable caching – this can greatly improve the performance.</li>
<li>It uses the <a href="https://fullcalendar.io/" rel="nofollow ugc">FullCalendar</a> library to show the calendar and can be fully customized within the Gutenberg block, shorcode attributes and the widget settings.</li>
<li>Calendar filtering.</li>
</ul>

Private Google Calendars

Display private and public Google Calendars on your Wordpress website.

Google Calendar Widget vs Private Google Calendars