Despite recent growth in surveillance capabilities there has been little discussion regarding the ethics of surveillance. Much of the research that has been carried out has tended to lack a coherent structure or fails to address key concerns. I argue that the just war tradition should be used as an ethical framework which is applicable to surveillance, providing the questions which should be asked of any surveillance operation. In this manner, when considering whether to employ surveillance, one should take into account the reason for the surveillance, the authority of the surveillant, whether or not there has been a declaration of intent, whether surveillance is an act of last resort, what is the likelihood of success of the operation and whether surveillance is a proportionate response. Once underway, the methods of surveillance should be proportionate to the occasion and seek to target appropriate people while limiting surveillance of those deemed inappropriate. By drawing on the just war tradition, ethical questions regarding surveillance can draw on a long and considered discourse while gaining a framework which, I argue, raises all the key concerns and misses none.