Methaqualone, sold under the brand name Quaalude (\ˈkwā-ˌlüd\), in the US and Mandrax in the UK and South Africa, is a sedative and hypnotic medication. It is a member of the quinazolinone class.

The sedative–hypnotic activity of methaqualone was first noted by researchers in the 1950s. In 1962, methaqualone was patented in the US by Wallace and Tiernan. Its use peaked in the early 1970s as a hypnotic, for the treatment of insomnia, and as a sedative and muscle relaxant.