Police found the statue at about 5:30 a.m. Sunday, broken off its foundation and tilted forward, The Orange Country (Calif.) Register reported.
The thieves apparently tied a chain around the statue and tried to pull it away using a pickup truck or other vehicle, police say.
"Either someone really didn't like Reagan or they tried to steal it so they can sell it for scrap metal," said police Sgt. Kirk Jacobi.
The statue has since been removed from its concrete base by the city.
The statue was dedicated on Oct. 9, commemorating the 100th anniversary of Reagan's birth. It was commissioned for about $60,000.
Officials have not yet said how much it will cost to repair the statue. An investigation into the attempted theft is under way.