Radioactive describes something undergoing radioactive decay, the process by which an unstable atomic nucleus emits radiation.

Radioactive may also refer to:

• Naturally occurring radioactive material
• Nuclear pharmacy, the preparation of radioactive materials for nuclear medicine
• Radioactive contamination
• Radioactive waste

• Radioactive (Yelawolf album), a 2011 album by rapper Yelawolf
• "Radioactive" (Gene Simmons song), a song from the 1978 album Gene Simmons by Gene Simmons
• Radio:Active the fourth album from British pop rock group McFly
• "Radioactive" (The Firm song), a song from the 1985 album The Firm by the English supergroup The Firm
• "Radioactive" (Swedish hard project), a swedish hard project formed by Tommy Denander in 2001.
• "Radioactive" (Imagine Dragons song), a 2012 song by Imagine Dragons
• "Radioactive" (Kings of Leon song), a 2010 song by Kings of Leon
• "Radioactive" (Marina and the Diamonds song), a 2011 song by Marina and the Diamonds
• "Radioactive" (Rita Ora song), a 2013 song by Rita Ora
• Radioactive Records, a record label
• Radioactive FM 96, a radio station, which broadcasts from Karachi, Pakistan
• Radioactive (film), a biographical film about Marie Curie

• Radioactive Man (disambiguation)
• Radio Active (disambiguation)
• Radioactivity (disambiguation)