Operational Research (OR) had its origins in the need to make decisions about the use of resources in support of national defence. The specific case was the invention of radar in the late 1930's and the military problem was to decide how this new technology could best be employed, in conjunction with the existing assets, such as fighter aircraft, for the air defence of the United Kingdom. It was, in short, necessary to conduct research into how military operations could be carried out, and hence the discipline was born. In fact, for the last 50 years, the military have been the major users of mathematical modelling. System Dynamics is, however, a relatively new tool in military analysis. This paper surveys a few published applications and suggests reasons why SD is particularly appropriate for certain classes of military problems. The paper then goes on to discuss the potential role of SD in the analysis of strategic problems. Finally, some problems of military theory are discussed.