420 may refer to:
Science and technology 420 (number), in mathematics 420 Bertholda, a main-belt asteroid 4:2:0, a chroma subsampling layout NGC 420, a lenticular galaxy
Cannabis culture 420 (cannabis culture), informal reference to cannabis use and celebrations on April 20 California Senate Bill 420 or the Medical Marijuana Program Act "420" (Family Guy), an episode of Family Guy "4-2-0" (song), a song by Kottonmouth Kings from Rollin' Stoned
Dates AD 420, a year in the 5th century of the Julian calendar 420 BC, a year April 20
Culture of India Section 420 of the Indian Penal Code, a law against cheating and dishonesty Shree 420, a 1955 Indian Hindi-language comedy-drama film, starring Raj Kapoor Chachi 420, a 1997 Indian Hindi-language comedy-drama film, starring Kamal Haasan Uyarthiru 420, a 2011 Indian Tamil-language film Mr. 420 (2012 film), an Indian Kannada-language romantic comedy film 420 IPC (film), a 2021 Indian Hindi-language crime thriller film
Other uses 4-2-0, a classification of steam locomotives 420 (dinghy), a class of double-handed racing sailboats "4:20", a song by Six Feet Under on the 1997 album Warpath +420, calling code of the Czech Republic Maserati 420, a saloon
See also 420th (disambiguation) List of highways numbered 420