A plug connector, in particular a modular plug connector, is provided for mounting on a circuit board. The plug connector can be assembled from a plurality of plug connector modules, wherein each plug connector module comprises at least one part. The plug connector modules have an insertion side and a connection side, wherein the insertion side can either be installed on the circuit board or else it contacts a connection side of a mating connector module. The plug connector modules can be connected by at least one connector. This makes it possible also to install modular plug connectors on a printed circuit board.