Reason is the analytic faculty of the human mind that maintains objectivity unto inspecting and organizing perceptions.

Reason may also refer to:

• The cause of something
• Rationality, the quality or state of being reasonable, based on facts or reason
• Reason (argument), a factor which justifies or explains

• Reason (programming language), an alternative OCaml syntax and toolchain created at Facebook
• Reason (software), a digital audio workstation

• Reason (magazine), a monthly libertarian magazine published by the Reason Foundation
• "Reason" (short story), a 1941 science fiction short story by Isaac Asimov
• Reason: Why Liberals Will Win the Battle for America, a 2010 book by Robert Reich
• Reason: the Only Oracle of Man, a 1785 book by Ethan Allen
• Reason, a fictional weapon system from Neal Stephenson's novel Snow Crash

• Reason (American rapper), an American hip hop artist

• Reason (Australian rapper), an Australian hip hop artist

• Reason (British rapper) (born 1970), a British hip hop artist, former member of Love City Groove
• Reason (South African rapper), a South African rapper

• Reason (The Fray EP), a 2003 EP by The Fray
• Reason (Melanie C album), a 2003 album by singer Melanie C
• Reason (Monsta X EP), a 2023 EP by Monsta X
• Reason (Officium Triste album), a 2004 album by doom metal band Officium Triste
• Reason (Selah Sue album), 2015
• Reason (Shaman album), a 2005 album by Brazilian power metal band Shamaan
• Reason (Violent Apathy album), 1995

• "Reason", a 2004 song by German dance act Diamond, re-released in 2015 as Cascada
• "Reason", a 2018 song by South Korean singer Song I-han
• "Reason", a 2021 song by Indian rapper and singer Abhi the Nomad, from Abhi vs the Universe
• "Reason", a 2023 song by South Korean girl group Dreamcatcher
• "Reason", a bonus track on the Cranberries' album Everybody Else Is Doing It, So Why Can't We?
• Reason (Nami Tamaki song), a 2004 song by Nami Tamaki
• Reason (No Angels song), a 2003 song by German pop band No Angels
• Reason (Yuzu song) a 2012 song by Yuzu

• The Reason Foundation, a public policy think tank based in Los Angeles, California, U.S.
• Order of the Reason, a medieval military order native to Spain
• Reason (surname)
• Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON), a radar system on board NASA's Europa Clipper mission to Jupiter's moon Europa
• Reason Australia, a political party in Australia

• Age of reason (disambiguation)
• No Reason (disambiguation)
• Reasons (disambiguation)
• The Reason (disambiguation)