Modern rock is a term commonly used to describe a rock music format found on commercial radio. Modern rock stations play new rock from a variety of artists, some of which wouldn't get airplay on active rock stations. More specifically, the modern rock format consists of commercial radio stations that primarily play alternative rock. As such, the format is also frequently called Alternative radio.

Generally beginning with late 1970s punk but referring especially to rock music since the 1980s, the phrase "modern rock" is used to differentiate the music from classic rock, which focuses on music recorded in the 1960s through the early 1980s. A few modern rock radio stations existed during the 1980s, such as WLIR-FM on Long Island and WFNX in Boston. Modern rock was solidified as a radio format in 1988 with Billboard's creation of the Modern Rock Tracks chart. The 1988 episode of the VH1 show I Love the '80s discussed INXS, The Cure, Morrissey, Depeche Mode, and Erasure as modern rock artists representative of that year. But it was the breakthrough success of the grunge band Nirvana in 1992 that resulted in a large number of American radio stations switching to the format. Modern rock is considered by some to be a specific genre of alternative rock.