Sulazepam is a benzodiazepine derivative. It is the thioamide derivative of diazepam. It is metabolised into diazepam, desmethyldiazepam and oxydiazepam^{[citation needed]}. It has sedative, muscle relaxant, hypnotic, anticonvulsant and anxiolytic properties like those of other benzodiazepines. It was never marketed.

Treatment of diazepam with phosphorus pentasulfide produces the corresponding thionamide, sulazepam.