Plan B may refer to:

• Plan B (Album), hit album by Too Phat,superstar hip hop duo from Malaysia.
• Plan B (magazine), a music and arts magazine from Brighton, England.
• Plan B (levonorgestrel), a brand name for progesterone-only emergency contraception in pill form. See Progesterone only pill.
• Plan B (album), the 8th album from Huey Lewis and the News
• Plan B (operating system), a distributed operating system derived from Plan 9 from Bell Labs
• Plan B (novel), an unfinished novel by Chester Himes
• Plan B (rapper), a UK hip-hop artist
• Plan B Skateboards
• Plan B (company), a production company founded by Paramount Pictures
• Plan B projekt (company), a Creative design company , that handles print media , and web portfolio design
• Plan B (covert action), a misinformation campaign by the CIA to pad figures about the military strength of the USSR during the Brezhnev era, to justify defense spending