L42 may refer to: HMS Brocklesby (L42), an ex-coaster taken up from trade that served in World War I for the British Royal Navy Lee–Enfield L42, a sniper rifle Mitochondrial ribosomal protein L42, a human protein Sako Model L42, a rifle Spanish landing ship Pizarro (L42) an engine in GM's Ecotec engine family a version of the Chaika L-4 amphibian aircraft