Abstract: A gun lock 10 to surround the trigger and trigger guard of a gun 11. The lock 10 has a pair of shield halves 13 and 14 which prevent access to the trigger. The shield halves 13 and 14 are held together by means of a threaded shaft 15 and threaded passage 22 which co-operate, in addition to a shackle member 23 which also extends between the shield halves 13 and 14. A key operable lock barrel 19 is operable to retain the shackle member 23 attached to the shield halves 13 and 14 and is operable to release the shackle member 23.