This chapter focuses on situational crime prevention, a method for reducing opportunities for crime by manipulating the immediate environment. It begins by charting the origins and development of situational crime prevention. It then describes how rational choice was later added as the model of offender decision making to underpin situational crime prevention. Three questions are then considered: Is rational choice the only possible theoretical underpinning for situational crime prevention? Is rational choice a satisfactory account of offender decision making? Does rational choice need to be supplemented for the purposes of crime prevention research and practice, and if so, with what?