Mumps and epidemic parotitis is a viral disease of the human species, caused by the mumps virus. Prior to the development of vaccination and the introduction of a vaccine (mumps vaccine), it was a common childhood disease worldwide, and is still a significant threat to health in the third world.

Painful swelling of the salivary glands (classically the parotid gland) is the most typical presentation. Painful testicular swelling (orchitis) and rash may also occur. The symptoms are generally not severe in children. In teenage males and men, complications such as infertility or subfertility are more common, although still rare in absolute terms. The disease is generally self-limited (Self-limiting (biology)), running its course before receding, with no specific treatment apart from controlling the symptoms with painkillers.