Sandy Casar (born February 2, 1979 in Mantes-la-Jolie, Yvelines) is a French professional racing cyclist.
Casar turned professional in 2000 after riding for Jean Floch-Mantes as an amateur. As a professional he has always ridden for FDJ.
Casar's talent was revealed in Paris-Nice 2002, which he finished second at 23 years old. He finished 13th in the 2003 Giro d'Italia, in front of climber Marco Pantani. He had his biggest win in a stage of the 2003 Tour de Suisse. He then finished 16th in the 2004 Tour de France, and sixth in the 2006 Giro d'Italia, 25 minutes behind winner Ivan Basso. Casar also won the Route du Sud in 2005.