A toy building set comprising a plurality of plate-shaped toy building elements (1, 2) with a thickness and having at least one through-going opening (5) provided at an edge of the toy building element (1, 2); and a plurality of coupling elements (3) for interconnecting at least two plate-shaped toy building elements (1, 2), said coupling elements (3) being each provided with at least two protruding coupling studs (7) that are complementary with the through-going openings (5) provided in the plate-shaped toy building elements (1, 2). The coupling studs (7) on the coupling elements (3) have a height that corresponds to or is smaller than half the thickness of the plate-shaped toy building elements (1, 2) at the through-going openings (5), thereby enabling two coupling studs (7) to engage with the same through-going opening (5) from each side of a plate-shaped toy building element (1, 2).