The Frenchman indicated back in August that he was considering his future with the team, who have accrued just 10 points this campaign, eight of which have come from Grosjean.
Late last month the 28-year-old revealed the existence of a get-out clause that would allow him to leave Lotus at the end of the season.
However, Grosjean has now reaffirmed his commitment to the Enstone-based team and will once again partner Pastor Maldonado in 2015.
"I'm very pleased, happy and proud to be part of Lotus F1 team for next year," Grosjean told Lotus' official website.
"I've spent a lot of time at the factory working with everyone, and the relationship I have with the team is very strong. We've had some good moments and tough ones and we always stay together, which makes it even more attractive for the future.
And, after a difficult year, Grosjean is hopeful that Lotus can challenge at the front in 2015 and try to return to their 2013 form, which saw them finish fourth in the constructors' standings.
He added: "It's easier to say than to do, but I firmly believe that you always learn much more from difficult rather than easy situations. Not only has the team learnt an enormous amount this season, but I think I've also improved massively.
"I really hope when I get in the car at pre-season testing I get that special feeling when you know it's going to be a good season. I'm not saying we will be back at our 2013 levels when we were extraordinarily good for the size of our budget that we had.
"Personally, I am hoping we can challenge the front runners, score a few podiums and points and get back into the top five in the constructors' championship and I want to taste champagne with the team again."