This thesis examines the validity of applying traditional small state theories to the study of New Zealand foreign policy. Increasingly such theories have been the target of criticisms which highlight their inability to account for diversity amongst states, as well as their failure to acknowledge the changing international environment. Critics stress the increased levels of interdependence that they believe provides more opportunities for small states to overcome the constraints they face thus rendering their propositions obsolete. To ascertain whether such criticisms are valid this paper applies small state theories to two ten year periods of New Zealand's foreign policy, 1944-1954 and 1984-1994. Evidence of the characteristics associated with small states are identified in both periods yet in significant areas its foreign policy behaviour diverged from that expected. In these incidences it is necessary to acknowledge the influence of variables from other theoretical perspectives utilised in the study of foreign policy and the interaction that occurs between these different perspectives. Thus whilst not rendering small state theories obsolete, the application of variables from alternative theories to the study of its foreign policy enables a more comprehensive multicausal examination than that provided by small state theories alone. New Zealand in both periods exhibited the characteristics of a small state and was therefore constrained in the way such theories identify, yet due to the changes in the international environment, and it's unique historical and geographical position, it was able to overcome these constraints. It is therefore necessary to be aware of alternative perspectives when applying small state theories to the study of New Zealand's foreign policy. The impact of environmental and societal determinants must be acknowledged, as must the focus be turned within small state theories from that of viability, to include the potential benefits small size can offer in an international arena increasingly characterised by interdependence.