A cap for a writing implement comprises an outer cap having open top and bottom ends with an inner cap having at its top a closed end and at its bottom an open end and coaxially connected to the outer cap by means of a plurality of radially extending ribs to define openings between the outer and inner caps. Flange elements are disposed below the openings for preventing the writing tip from entering the openings and guiding it toward the inner cap, the flange opening elements being circumferentially spaced apart from one another by means of slits in alignment with the ribs.