The 53-year-old Democrat was re-elected in 2000 and says he wants to devote more time to his family although he has seen his popularity shrink recently as Washington's economy struggles.
The Seattle Times said that Democratic Attorney General Christine Gregoire is considering running. There has not been a Republican governor in Washington since 1984.
Locke has not announced his plans for the future.
2014: The Year in Music [PHOTOS]