In a recent high-profile terrorism case in the U.K., a British-born ISIS sympathizer named Junead Khan was convicted for plotting to attack and kill U.S. military personnel stationed in Britain. His plan was to ram into a vehicle carrying American soldiers and then behead the incapacitated victims. Had police intervened at any point, the intention was to detonate a pressure cooker bomb, committing suicide in the process and maximizing the number of casualties. Far from being an isolated case, this is just one of a long list of attacks on military personnel which have been planned and sometimes executed by Western jihadists. Indeed, Khan appears to have been directly inspired by the events of May 22nd, 2013, when an off-duty British soldier, Fusilier Lee Rigby, was run down and hacked to death by two extremists on the streets of Woolwich, east London. Plots and attacks like these understandably grab headlines and result in at least temporarily heightened force-protection measures. However, little effort has been made to systematically analyze Western jihadist threats to the military, which of course are not limited to the U.K. and are both diverse and ongoing. Drawing upon a variety of cases involving Europe, North America and Australia, this article identifies a range of overlapping external and internal threats and discusses implications for military security.