The service's new policy now explicitly states that blocking advertisements within Spotify can result in an immediate termination of a user's account.
Spotify's free service allows users to listen to music without a monthly subscription, but plays advertisements periodically and provides limited account functionality compared to Spotify Premium.
Some Spotify users have used modified accounts and ad-blockers to circumvent the advertisements being played, and Spotify has been cracking down on this activity.
In March 2018, Spotify stated that two million of its free users blocked advertising.
"Spotify respects intellectual property rights and expects you to do the same," it said.