The invention comprises a modular support system (7) for optical fiber trays (10) comprising: at least one central module (21) for supporting the optical fiber trays, the central module being adapted to be positioned side-by-side with a plurality of central modules supporting the optical fiber trays, wherein the central module further comprises a fixing structure (34, 35) for attaching at least one additional fiber management module (41, 51) to the central module. The invention further comprises a kit of parts for a modular support system for optical fiber trays as well as an optical fiber organizer.