Tomislav "Tomo" Miličević is a Bosnian-American musician and record producer. He was the lead guitarist of the rock band Thirty Seconds to Mars from 2003 to 2018. Born in Sarajevo but raised in the United States, Miličević moved to Troy, Michigan, in the early 1980s, where he became active in the local heavy metal scene and played in a number of bands, co-founding Morphic. In 2003, he joined Thirty Seconds to Mars, with whom he achieved worldwide recognition in the mid-2000s after recording the band's second album A Beautiful Lie (2005). Its full-length follow-ups, This Is War (2009) and Love, Lust, Faith and Dreams (2013), received further critical and commercial success.

Thirty Seconds to Mars is an American rock band from Los Angeles, California, formed in 1998. The band consists of brothers Jared Leto and Shannon Leto. During the course of its existence, it has undergone various line-up changes with the Leto brothers being the only consistent members.