The present disclosure relates to a corner connector for hollow profiles, including a base element having a first and a second wall section connected at a right angle and in one piece to each other on one respective lateral edge that forms a connecting edge, a first guide and connection groove extends from a lateral edge that is adjacent and in parallel to the connecting edge, and at least one essentially plate-shaped, rectangular additional element, wherein two guide and connection projections protrude from its inner side complementary to the first guide and connection grooves which can be inserted into the first guide and connection grooves in a direction parallel to the connecting edge and, in the fully inserted position, secure the additional element flush on the base element in order to form a third wall section arranged at a right angle to the first and the second wall section.