The government-funded distance-learning university has issued a tender document and is planning to hold a pitch later in the year.
Agencies have been given until the middle of next month to signal their intention to pitch for the account, with up to ten agencies due to be involved in the first stage.
Work will include data management, customer recruitment and acquisition campaigns, e-mail marketing and SMS marketing.
The OU currently uses DigForFire DMG and Response One to handle its marketing communications.
Last November, the OU handed its £8 million media planning and buying account to Rapp Media.
The agency won the business after a final shoot-out against Mindshare. Zed Media, which had been the incumbent since 2001, was eliminated at an earlier stage.