Sharing the Outlook Calendar
Log in to your Office 365 account and navigate to Outlook by clicking on the app launcher (the nine dots in the top left corner) and selecting the Outlook icon.
The O365 app launcher with Outlook highlighted.
Click on Settings > View all Outlook settings.
Open Calendar > Shared Calendars.
Outlooks Calendar settings with the shared calendar settings highlighted.
In the "Publish a calendar" section, choose the calendar you want to share (if you've only got one Calendar set up it will just be called "Calendar"), select "Can view all details" in the second dropdown, and click "Publish."
This will create two links: an HTML link and an ICS link. The HTML link allows people to view your calendar in a browser and the ICS link will enable people to import your calendar into their calendar program.
Click the ICS link, and a menu will appear. Select the "Copy link" option to copy the link to your clipboard.
Adding Outlook Calendar to Google Calendar
Open up Google Calendar and click on the "+" sign next to "Other calendars."
In the menu that appears, click "From URL."
Paste the ICS link you copied from Outlook and click "Add calendar."
Exit out of Settings and check that the calendar has been added.
The Outlook calendar displayed in Google Calendars.
The calendar will sync up with your Outlook calendar as long as you stay subscribed. It may take a few minutes for changes to the Outlook calendar to be reflected in Google Calendar (or it may be almost instantaneous, depending on when Google looks for new information), but your Outlook events should appear pretty quickly.
Customizing the Calendar's Look and Feel
Your calendar is now synced but to make things a little more user-friendly, you can change the display name from the unhelpful "Calendar" to something else.
First, hover over the calendar, click the three dots that appear next to it, and click "Settings."
Google Calendar's Settings option for the shared calendar.
In the "Name" text box at the top of the page, change the name of the calendar to something more meaningful. Then click the back arrow in the top left to exit the Settings.
The Settings for the calendar with the Name field highlighted.
The calendar now displays your new name.
The shared calendar renamed to something meaningful.
Remove an Outlook Calendar from Google
If you hover the cursor over the calendar, an "X" will appear. Clicking this will unsubscribe you from the calendar. You'll have to repeat these steps and re-enter the ICS URL to subscribe again.