"Hey There Delilah," written by Tom Higgenson, is the third single released from the band Plain White T's 2005 album All That We Needed. In June 2007, over two years after the song's release, it became the band's first hit in the United States, eventually reaching #1 on the Billboard Hot 100 in July. From July 3, 2007 through July 28, the song was the number one most played song on the radio, and the number one downloaded song on the U.S. iTunes Music Store. Since its release, "Hey There Delilah" has been covered by many artists worldwide in one form or another.

It was the first number one single for the Plain White T's, and the second number one for the Hollywood label, after "The Way" by Fastball in 1998. It also reached number two in the UK. The song ended 2007 as the year's 14th biggest-selling single in the UK.

Although "Hey There Delilah" is from the Plain White Ts' third album, All That We Needed, since the single's popularity new versions of the intervening fourth album, Every Second Counts, have "Hey There Delilah" added as a bonus track with a string section augmenting the original recording. The music video for the song was directed by Jay Martin.

The song was written after Higgenson met Delilah DiCrescenzo, a nationally ranked American steeplechase and cross country runner.

Timemagazine named "Hey There Delilah" one of The 10 Best Songs of 2007, ranking it at #7. Music critic Josh Tyrangiel called it "an intimate love song that's damn near universal." Tyrangiel praised the Plain White T’s for managing to make another "aching guy reaching out to distant girl song feel fresh," singling out singer Tom Higgenson’s otherwise imperfect voice and "nasal delivery [for making] the nearly-comic sincerity of the lyrics seem completely genuine."

The song was a 2008 Grammy Award nominee for Song of the Year and Best Pop Performance by a Duo or Group with Vocal, but didn't win either award (Amy Winehouse and Maroon 5 won the awards).

On VH1's Top 40 Videos of 2007, "Hey There Delilah" was #8, ahead of "If Everyone Cared" by Nickelback and behind "Say It Right" by Nelly Furtado.

The song's sincere lyrics and simple structure have made it the target of numerous parodies.