Several notables have been named William Walker:

• William Walker, briefly ruler of Nicaragua
• William Walker, composer in the shape note tradition, author of Southern Harmony
• William Walker (1808-1896), missionary in Gabon
• William Walker , assistant to George Eastman
• William Walker , leader of the Kosovo Verification Mission
• William Walker, the diver who saved Winchester Cathedral from collapse
• William Walker (main character in S.M. Stirling's Island in the Sea of Time series)