A fluid dispenser comprising: a fluid reservoir (1) provided with a neck (11) that is externally threaded and that internally defines an opening (10) that communicates with the inside of the reservoir, the neck (11) forming at least one helical thread (12); a dispenser head (2) mounted on the neck (11) of the reservoir (1), the head (2) comprising: a dispenser member (3), such as a pump or a valve; a pusher (4) for actuating the dispenser member (3); and a fastener member (5, 6) engaged both with the threaded neck (11) of the reservoir (1) and with the dispenser member; the fluid dispenser being characterized in that the fastener member (5, 6) comprises: a deformable and malleable skirt (51) for coming into engagement with the threaded neck (11); and a rigid hoop (6) that is engaged around the skirt (51) so as to push the skirt radially against the threaded neck (11) in such a manner as to deform the skirt (51) against the thread (12) so as to create a thread imprint (530) in the skirt.