"I believe that at this time I can be more effective in a decisive role to help elect other true public servants to office," Palin said in a statement.
The former Alaska governor said she gave the matter serious consideration and thanked her supporters.
"Know that by working together we can bring this country back - and as I've always said, one doesn't need a title to help do it," she said.
Her announcement comes one day after New Jersey Gov. Chris Christie announced he would also not be running for president.
Without Christie and Palin, Mitt Romney and Rick Perry remain the front runners of the race three months before the first GOP voting.