"Should've Known Better" is a hit song written, composed, and performed by American rock singer Richard Marx.

It was released in September 1987 as the second single from his Triple Platinum-selling self-titled debut album.

Marx became the first solo artist in recording history to reach the top three of the Billboard Hot 100 with four singles from a debut album.

Released in September 1987 as the second single from his debut solo album, "Should've Known Better" entered the U.S.

Billboard Hot 100 on September 26, 1987 at number 64, the highest debut of the week.