Rellingen is a municipality in the district of Pinneberg, in Schleswig-Holstein, Germany. It is situated approx. 7 km east of Pinneberg, and 10 km northwest of Hamburg. Population as of 30.06.2005 is 13.693. The total land area are 13,19 km².
Rellingen can be reached from Autobahn 23. The Hamburg S-Bahn and bus system is also connected to Rellingen.
Rellingen is famous for its Lutheran church. The architect was Cay Dose. The previous church building was damaged badly during the Thirty Years War. It was rebuilt and extended. The church has an octagonal shape and has a church tower which is leaning to one side.