Before we start, if you’re just wanting to email all members of the group you can “select all” then choose “E-Mail Users” from the action menu when viewing the group membership within SharePoint. This opens an Outlook window with all the addresses pre-populated.

But, if you still need an excel sheet of membership for another purpose (perhaps to format a sign-in sheet, generate documents with mail merge, share the list with others, etc.) follow these steps:
- With the group open in SharePoint, copy the URL and note the ID number at the end of the URL
- Open a new excel workbook
- From the “Data” tab, select “New Query” –> “From Other Sources” –> “From OData Feed“
- Paste the group URL in the prompt but delete everything after the site address and replace with the following, replacing “6” with your group’s ID from step 1
/_api/Web/SiteGroups/GetByID(6)/Users - When prompted for login credentials you’ll use “Windows” for on-prem/server and “Organizational account” for O365.
- Click “Edit” once the group loads so we can choose which columns to keep/delete
- Ctrl+click the column headers you want to keep
- Right-click a header of a column you’re keeping and select “Remove Other Columns”
- Close and Load
- You should now see your group membership and email addresses (and any other fields you kept). Save this somewhere and, if updates are made in the future, just click “Refresh all” to bring in new members and remove old.
Updated 8/8/2019: Added step 5 to show the login credentials prompt.