Frédéric Diefenthal (born 26 July 1968 in Saint-Mandé) is a French actor and director.

Diefenthal grew up in Saint-Puy in southwestern France. He is Jewish. Prior to acting, Diefenthal pursued apprenticeships in the hotel industry, hairdressing and was also an apprentice pastry chef. He began studies in architecture before switching to drama classes. Diefenthal began acting in the early 1990s; he held a main role in the French television series Le juge est une femme (The Judge is a Woman), where he first gained a degree of notoriety. He also played a major part in the French Taxi series.