Thirty Seconds to Mars (commonly stylized as 30 Seconds to Mars) is an American rock band from Los Angeles, California, formed in 1998. The band consists of Jared Leto (lead vocals, guitar, bass, keyboards), Shannon Leto (drums, percussion) and Tomo Miličević (lead guitar, bass, violin, keyboards, other instruments).

Thirty Seconds to Mars has consistently enjoyed sold out tours and numerous headlining festival slots. The band is noted for its energetic live performances and for fusing many music genres. They have been compared to the sounds of bands such as Pink Floyd, The Cure, Tool, and U2, for their philosophical and spiritual lyrics, concept albums and their use of experimental music. Thirty Seconds to Mars has received several awards and accolades throughout their career, including a Guinness World Record, and has been included in the Kerrang! list of best artists of the 2000s.The band has been an active supporter of various social and philanthropic causes.

Thirty Seconds to Mars launched a website, called, to provide information about environmental issues and ways to participate in environmental activities. People can make donations through the site to support the Natural Resources Defense Council. In 2006, Jared Leto created the cover art for The 97X Green Room: Volume 2, a compilation of live music that includes a Thirty Seconds to Mars song, which proceeds from the sales benefited The Nature Conservancy. During their Welcome to the Universe Tour, the group worked to develop strategies that would minimize fuel consumption to offset the impact that the tour would had on the environment.

In June 2008, the band joined Habitat for Humanity to work on a home being repaired and renovated through the Greater Los Angeles Area’s “A Brush With Kindness” programme. In advance of the build, the band organized an auction of “build slots” to give fans the opportunity to volunteer alongside them. In less than a week, six extra workers were enlisted and over $10,000 was raised to fund additional Habitat for Humanity projects. Thirty Seconds to Mars fans, termed as the Echelon, started several philanthropic organizations and projects with the purpose of supporting various charities and humanitarian causes.

After the 2010 Haiti earthquake, Thirty Seconds to Mars raised $100,100 for Haitian relief through a charity auction. The band has also supported the Haitian population through the Echelon project “House for Haiti” and Hope For Haiti Now telethon special. The group auctioned a quantity of items raising funds to help the Red Cross assist people affected by the 2011 Tōhoku earthquake and tsunami. The band contributed one dollar per concert ticket sold on the Carnivores Tour to the charity Music for Relief to support disaster relief and programs to protect and restore the environment.