A writing instrument that includes a body extending along a central axis between a front end provided with a writing tip and a rear end, the body presenting a grip zone and comprising at least first and second elements that are assembled together, and a tubular grip sleeve covering the grip zone at least in part. The grip sleeve presents at least one projection extending towards the central axis, and the first and second body elements define a housing adapted to receive the projection of the sleeve, the projection being pinched in the housing by the first and second assembled-together elements.