The New Zealand Labour Party (NZLP) and the Australian Labor Party (ALP) share many similarities in terms of their ideology, support base and electoral performance. Labour and ideas travelled regularly between New Zealand and Australia. Australian influence was evident in the early NZLP leadership, and New Zealand influenced ALP policy regarding arbitration and age pensions. Subsequently, the NZLP and ALP have enjoyed similar national electoral records and followed broadly similar policies. However, there were always important divergences, particularly in terms of the timing of consolidation and formation of government, the impact of different state structures, the degree of support from farmers, and racial policy. This article surveys the parameters of the shared experience through examining the two parties’ political and social environments, their support bases and their ideology and policy.