I consider Monday the start of my week, so I like to make sure my Calendars are setup properly.
- Open you Google Calendar in your browser
- Click the Gear in the top bar
- Click settings
- Scroll to "View options"
- In Start week on dropdown menu, change "Sunday" to "Monday"
- Open the Calendar app on your Mac
- Click Calendar in the menu bar
- Click Preferences
- In General, find Start week on: and change it from "Sunday" to "Monday"