The actor apparently exited the follow-up to the 1994 hit comedy amid clashes with New Line and Warner Bros over their perceived lack of interest in the movie, sources told ET Online.
Carrey officially confirmed his departure from the film in a statement, saying: "I would have thought Dumb and Dumber To was a no-brainer, after all it's implied in the title."
The news comes two months after Dumb and Dumber To co-director Peter Farrelly announced that Carrey and Jeff Daniels would return for a film set in the present day.
Carrey had first expressed an interest in Dumb and Dumber To last summer while promoting Mr. Popper's Penguins.
The original Dumb and Dumber made $279m (£177m) at the international box office upon release in 1994.
Watch a Dumb and Dumber trailer below: