This thesis examines the performance of the intelligence collection organisations of the armed services of New Zealand during the Second World War. It considers the intelligence bodies of the Navy, the Army and the Air Force and looks at their growth, development and demise, and assesses their effectiveness as intelligence organisations. The question of how much New Zealand could be expected to achieve in the field of intelligence arises, not least because New Zealand was demographically small, had a long coastline and was geographically relatively remote. How much could New Zealand contribute to the Allied cause in intelligence terms is another issue, and what forms did any participation take? Were there lessons to be learned from the wartime experience (there were, but they went for the most part largely unheeded)? New Zealand, like other countries, had a fragmented approach to intelligence collection, making for a degree of complexity over a range of activity, despite the intelligence organisations being of modest size. The examination of the organisations in this thesis includes multi-service and multi-departmental dimensions along with the production of useful intelligence. Whether good use was made of intelligence collected is another matter. There was a substantial amount of liaison, contact and practice between departments of state as to various aspects of intelligence, the Organization for National Security and coastwatching being two notable areas. The overarching role and limitations of the Organization for National Security with regard to intelligence is explored, and the development of a combined intelligence centre examined. The participation of New Zealand signals intelligence organisations in the great Allied interception offensive is detailed, along with the mundane but fundamental task of coastal surveillance. The establishment and spectacular decline of the first local independent security service is traced. Both the intelligence and security aspects of the Army's operationally deployed units are covered, along with the growth of RNZAF air intelligence. The effectiveness of all of these organisations could hardly be expected to be uniform, and indeed it was not. Some bodies succeeded in their collection roles beyond expectations, others were reasonably effective, and two organisations failed dismally in different ways, for a number of reasons. If a pattern emerges at all, it is that small single service component-type intelligence sections collecting operational intelligence were the most effective New Zealand intelligence organisations. Operational focus and. operational requirements underlay the drive for successful collection. Most significant within the Allied context were the signals intelligence bodies. At the other end of the scale, larger co-operative interdepartmental New Zealand intelligence ventures failed to deliver projected results. New Zealand's armed forces had an interesting variety of intelligence contributions during the Second World War. Of these, the most effective organisations collected intelligence to meet directed operational requirements.