The world of humanitarian assistance has grown significantly in scope and professionalism over the last fifty years. However, psychology has had little impact on work in this field. There are signs of this circumstance changing, with psychologists beginning to make contributions in a number of areas of activity. The purpose of this paper is to (1) identify the constraints that have limited the previous contribution of psychology in the arena of humanitarian assistance and (2) map areas where contributions have begun to be made, or offer particular potential for future contribution. The broad assertion of the paper is that the obstacles to appropriate application of psychological knowledge in the furtherance of the work of humanitarian assistance agencies are very real but, with due sensitivity, flexibility and breadth of vision, there are many areas of the discipline of psychology that can make a meaningful contribution to the conceptualization and implementation of humanitarian assistance.