Speaking to documentarian Morgan Spurlock at the Mipcom sales mart in Cannes, creator Groening said that the Simpsons team became "frustrated" over the time it took to make the first feature.
Groening said: "It took 18 years to get around to doing the movie. We got very frustrated. We thought it would take two years but it ended up taking four. Some day maybe we'll do another one - but don't hold your breath."
Discussing when the animated show, now in its 21st season, will finish, Groening remarked: "We cannot predict the end because we can't believe we are still here today."
Showrunner Al Jean added: "We are contracted to do two more seasons. I gave up predicting the end a long time ago."
Simpsons producer David Mirkin recently told DS that the show's creative team are still "in therapy" after going through the trauma of producing a movie.