"Hanging by a Moment" is a song by American alternative rock band Lifehouse. It was the first single released from their debut studio album, No Name Face (2000), issued through DreamWorks Records. The track was written by lead singer Jason Wade, who said that he wrote the song in about five minutes without thinking about what would happen to it. It was produced by American record producer Ron Aniello and was mixed by Brendan O'Brien. Musically, "Hanging by a Moment" is a post-grunge song that contains influences of alternative rock.

The song was first released as a radio single on September 25, 2000, rising slowly on the US charts and eventually peaking at number two on the Billboard Hot 100, becoming the band's most successful single on the chart and the most successful song of 2001 in the US. The track became an international success as well, peaking atop the Australian Singles Chart for five weeks and reaching the top 40 in the Netherlands, New Zealand, and the United Kingdom. In 2001, the song was certified double platinum by the Australian Recording Industry Association (ARIA) and was the most-played radio track of that year in Canada. The song received positive reviews from critics, who applauded its instrumentation.

The official music video for the song premiered on Vh1.com on December 7, 2000. In the video, Wade is seen singing the lyrics of the song in many locations around a town. The band went on tours with Matchbox Twenty and 3 Doors Down as an opening act before going on their first headline tour that featured rock band the Calling and singer Michelle Branch.