An optical fiber terminating assembly has an outer body (10), a first member (11) locatable in the outer body (10) and which carries a protruding length of optical fiber (36) which locates an alignment structure (44, 45) and a housing (12) locatable in alignment with the first member (11). The housing (12) has an access opening for receiving an optical fiber (52, 53) to be terminated so that the fiber can be located in the alignment structure in abutment with the optical fiber length (35). The housing has a compartment (47) which receives a heat responsive adhesive element (57), a saddle (58) and a resistor (59). When a current is passed through the resistor, the heat generated is transmitted by the saddle to the adhesive which melts and flows around the optical fiber (52, 53) to secure it in position in abutment with the optical fiber length (35).