In February 2015, Manor Marussia announced Stevens as one of their drivers whilst bringing substantial funding to the team, along with Roberto Merhi. Marussia attended the Australian Grand Prix but did not compete due to a technical issue. In the Malaysian Grand Prix Stevens drove the Marussia car for the first time in Practice 1. However, he did not compete in qualifying or the race because of a problem with the fuel system. In the Chinese Grand Prix Stevens finished his first race for Marussia in 15th place ahead of his teammate Merhi after being lapped twice by race winner Lewis Hamilton. Stevens finished ahead of Merhi in Bahrain and Spain. He finished behind Merhi in the Monaco Grand Prix in 16th. In the Canadian Grand Prix he qualified behind Merhi but moved up to 17th due to penalties to Jenson Button, Sebastian Vettel and Max Verstappen. In the race on lap 52, Romain Grosjean of Lotus was lapping Stevens but cut his left rear tyre while doing so which caused both drivers to make an emergency pit stop. The mechanics of both Lotus and Marussia had little time to react to their drivers pitting so that meant both Grosjean and Stevens took long pit stops. Stevens complained to his team on the radio about the incident. Grosjean received a 5-second penalty for the collision but Stevens had dropped from being 4 seconds behind Merhi to a minute behind him. However, Merhi was forced to retire on lap 56 after a drive-shaft issue. Stevens eventually finished in 17th place, 4 laps down on race winner Lewis Hamilton. After the race, Grosjean apologised to Stevens for the incident. During the later races of the season, Merhi was replaced by Alexander Rossi who outpaced Stevens in 3 of 4 races.