"Heartache Tonight" is a song written by Don Henley, Glenn Frey, Bob Seger and J. D. Souther, recorded by the Eagles and features Glenn Frey on lead vocals. The track was included on their album The Long Run and released as a single in 1979. It reached No. 1 on the U.S. Billboard Hot 100 in November of that year and was certified Gold by the Recording Industry Association of America representing one million copies sold. It was the Eagles' final chart-topping song on the Hot 100.

The recording received a 1979 Grammy Award for Best Rock Performance by a Duo or Group with Vocal. The song originated from an electric jam session between Glenn Frey and J. D. Souther who would visit Frey's home in Los Angeles whenever he was in town on tour. Frey and Souther wrote the first verse while listening to Sam Cooke songs. In the heat of jamming, Frey called Bob Seger on the phone and sang him the verse. Seger then blurted out the chorus. According to Frey, "J.D. [Souther], Don and I finished that song up. No heavy lyrics - the song is more of a romp - and that's what it was intended to be. The song was covered by country music singer John Anderson on the tribute album Common Thread: The Songs of the Eagles and was also covered by Michael Bublé on his album Crazy Love.