30 Seconds to Mars is the debut studio album by American rock band Thirty Seconds to Mars. It was first released on August 27, 2002, by Immortal Records and distributed by Virgin Records. The album was produced by Bob Ezrin, Brian Virtue, and Thirty Seconds to Mars, and was recorded in rural Wyoming during 2001 and early 2002. It had been in the works for a couple of years, with lead vocalist Jared Leto writing the majority of the songs.

30 Seconds to Mars was described as a concept album centering on human struggle and self-determination, characterized by personal lyrics that use otherworldly elements and conceptual ideas to illustrate a truthful personal situation. The album incorporates progressive sounds with influences and elements from new wave, space rock, and electronica. Upon release, 30 Seconds to Mars received mostly positive reviews from music critics, who commended the album's lyrical content and the band's musicianship, which has been compared to the works of Pink Floyd, Tool, and Brian Eno.

The album debuted at number 107 on the Billboard 200 and number one on the US Top Heatseekers. It was a slow-burning success that eventually sold two million copies worldwide. It produced two singles, "Capricorn (A Brand New Name)" and "Edge of the Earth". Thirty Seconds to Mars promoted the album by opening concerts for bands such as Puddle of Mudd, Incubus, Sevendust, and Chevelle.