Google's widely used free email service was disrupted for 18 minutes on Saturday, with the extent of the problem yet to be disclosed.
The trouble started at 12.30am IST on Saturday.
It was unclear what triggered the outage, which affected users in at least India, Britain and the United States.
Some US Gmail users were unable to access their accounts, and an online Google Apps dashboard tracking the status of the Internet titan's services indicated a problem at the email service.
Google did not immediately respond to an inquiry regarding the nature and severity of the Gmail disruption.