"Say It Ain't So" is a song by American rock band Weezer. It was released as the third and final single from the band's self-titled 1994 debut album on May 15, 1995. Written by frontman Rivers Cuomo, the song came to be after he had all the music finished and one line, "Say it ain't so".[3] Cuomo made a connection to an incident in high school where he came home and saw a bottle of beer in the fridge. He believed his mother and father's marriage ended because his father was an alcoholic, and this made him fear the marriage between his mother and step-father would end this way as well.[4] "Say It Ain't So" is widely considered one of the band's best songs. In 2015, Loudwire ranked the song number three on their list of the 10 greatest Weezer songs,[5] and in 2021, Kerrang ranked the song number two on their list of the 20 greatest Weezer songs.[6] In 2008, Rolling Stone ranked "Say It Ain't So" number 72 on their list of "The 100 Greatest Guitar Songs of All Time."[7] Pitchfork included the song at number 10 on its "Top 200 Tracks of the 1990s".[8]