This thesis seeks to explore the relationship between temporary migration and wage inequality in Aotearoa New Zealand. The transition in migration policy preferences in Aotearoa New Zealand, moving away from traditional source countries to a human capital regime, and subsequent changes in policies, particularly in the past two decades, have influenced the growth of temporary migrants and alterations in their nationality composition. Moreover, migration policies and regulations establish differentiated status among temporary migrants based on skills and visa status, incorporating limitations on changing employers, the type of employment opportunities available to migrants, and the duration of their visas. In this context, this thesis argues that the interplay between the stratified status of temporary migrants shaped by the migration system and their nationality composition, along with other attributes such as skills, occupations, and demographic composition, may impact wage inequality among this group. The thesis includes three interconnected quantitative studies to offer a detailed exploration of the relationship between temporary migration and wage inequality in Aotearoa New Zealand, analysing different linked administrative data available in the Integrated Data Infrastructure of Statistics New Zealand. The first study focuses on the effects of high volume of international migration on income inequality in the labour market at the national level. The population sub-groups decomposition approach is employed to disentangle within-group and between-group contributions of different population sub-groups to overall income inequality. The study reveals that recent migrants, predominantly constituting temporary migrants, experience the highest level of income inequality compared to earlier immigrants and the New Zealand-born population. The second study investigates the role of multiple factors on wage inequality among temporary migrants, employing the Shapley-value regression-based decomposition approach. The study identifies two main factors that influence wage inequality in the context of temporary migration: the migration system, which imposes varying conditions for migrants based on skills and visa status, including restrictions on employer switching, types of employment, and visa duration; and the composition of migrants, emphasizing how shifts in the nationality composition can impact wage inequality due to racialized discrimination in the workforce. The third study investigates the wage gap between temporary migrants from UK, Ireland, North America, and South Africa (group A) and those from other nationalities (group B), given that migrants in group A are predominantly white while those in group B may be perceived as racialized minorities distinct from the native population of Aotearoa New Zealand. The study uses the unconditional quantile decomposition method to examine whether the wage gap results from nationality-specific differences in migrants' characteristics or variations in nationality-specific returns to these characteristics. The findings reveal that the structural effect is the primary factor explaining the wage gap across the entire wage distribution, possibly indicating nationality-based discrimination. The impact of this discrimination decreases at the bottom and middle quantiles over time but shows a slight decline at the top end of the wage distribution. The study highlights that the migration system, which establishes a stratified status among migrants based on skills and remuneration bands, coupled with the nationality composition of temporary migrants, may contribute to the decrease in the wage gap at the bottom and middle quantiles. The significance of these insights lies in the finding that, instead of serving as a neutral mechanism to address labour market gaps, the rules and regulations within temporary migration systems play a role in creating the wage inequality among temporary migrants. Overall, the thesis provides both a detailed examination of inequality as it pertains to temporary migrants as well as providing key insights into the immigration dynamics associated with employment, migration policy, nationality and income. This dual emphasis on both inequality and immigration enriches the research, making noteworthy contributions to the literature on temporary migration, discussions surrounding social and economic inequality, and inquiries into social inclusion within Aotearoa New Zealand.