HBO Films said Wednesday that Moore will star in the film "Game Change," which follows John McCain's 2008 presidential campaign from when he chose Palin as his running mate through their defeat in the general election.
The film is based on the bestselling book of the same name.
No other cast members were announced, and HBO did not say when production on the film might begin.
Moore is a four-time Academy Award nominee. Last year, she starred in the critically acclaimed film "The Kids Are All Right."