«Turn It Up (remix)/Fire It Up» is a the third single by American rapper Busta Rhymes released from his second studio album, When Disaster Strikes (1997). The original version, which appears on When Disaster Strikes, takes a sample of «Love and Happiness» by soul singer Al Green. However, when issued as the third official single from When Disaster Strikes in the spring of 1998, the remix had now contained a sample of the 1980s TV series, Knight Rider, and under a new title «Turn It Up (remix)/Fire It Up». The song, nonetheless, became Rhymes’ third top-ten hit on the Billboard Hot 100, reaching number ten. It also became a hit on the rap (#1), dance (#2), and R&B charts (#7). Internationally, the single was a major success, reaching number two in the United Kingdom and number three on the Canada.

This song was sampled by Panjabi MC for his breakout single «Mundian To Bach Ke«.

The song was also featured on the soundtrack to the 1998 Jennifer Love Hewitt film Can’t Hardly Wait.