"I am the greatest" is a catch-phrase of American boxer Muhammad Ali.

I Am the Greatest or I'm the Greatest may refer to:

• I Am the Greatest: The Adventures of Muhammad Ali, a cartoon television series featuring (and voiced by) Muhammad Ali
• I Am the Greatest (Cassius Clay album) (1963), or its title song
• I Am the Greatest (A House album) (1991)
• "I'm the Greatest", a 1973 song by Ringo Starr from Ringo
• "I Am The Greatest", a 1966 song by Spitfire from Electric Colour Climax
• "I'm The Greatest", a song by Eric Morris and Buster's All Stars
• "I'm The Greatest", a 1972 song by Old Shatterhand
• "I'm The Greatest", a 1964 song by Ross McManus and the Joe Loss
• "I Am the Greatest", a 2015 song by Logic on the album The Incredible True Story