Georges Constant Mandjeck (born 9 December 1988 in Douala) is a Cameroonian football midfielder who plays for Turkish club Kayseri Erciyesspor in Spor Toto Süper Lig.

Mandjeck moved to Kayseri Erciyesspor at a fee of €1.000.000. He signed a contract until 2016.

Mandjeck was part of Cameroon's squad for the 2008 Summer Olympics. He came on as a substitute in their first group game against South Korea, where he scored a goal to earn Cameroon a 1–1 draw. He made his second appearance in the team's third group game, a goalless draw against Italy, where he was sent off for stamping on the foot of Antonio Nocerino