|Full name||Gert Jan Timmerman|
|Born|| 15 April 1956
|ICCF World Champion||1996-2002|
Gert Jan Timmerman (born 15 April 1956) is a Dutch chess player, most famous for being the fifteenth ICCF World Champion in correspondence chess, 1996-2002. Before becoming the fifteenth World Correspondence Champion he won Final B of the 5th World Cup between 1987 and 1994.
He tied for second place behind Mikhail Umansky in a "champion of champions" tournament, the ICCF 50 Years World Champion Jubilee. This was a special invitational correspondence tournament involving all living former ICCF World Champions.