A foldable wheelchair frame includes two side frame components, respectively a left and a right side frame components, each mounting front and rear wheels. The side frame components being connected together for relative folding movement between an erected position and a folded position by a foldable link extending between the two side frame components. The foldable link includes at least one central strut disposed between the two side frame components and connected to each side frame component by at least two connecting arms. First left and a second left connecting arms are connected to the left side frame component, and first right and second right connecting arms are connected to the right side frame component. Each of the connecting arms being pivotally connected at one end to one of the side frames and at one other end to the central strut such that the side frame components move closer to each other and said central strut moves along a longitudinal direction when the wheelchair frame moves from its erected position to its folded position. The central strut has at least one locking element that defines at least one left abutment (26a), respectively one right abutment, against which abuts a left locking pin (27a), respectively a right locking pin, protruding from the lower or upper face of one of the first left and the second left, respectively the first right and the second right, connecting arms in a vertical direction, when the wheelchair is in its erected position.