There is substantial evidence that suicidal behaviour is disproportionately observed among those with lower socioeconomic positions. Prior literature suggests that policy measures tackling severe socioeconomic deprivation may have impacts on decreasing the health gaps. Yet, little research has been conducted to examine the effects of social and welfare policies on suicidal behaviour and its inequality. This is in part because the understanding of the socioeconomic inequity in suicidal behaviour has been limited by the strong biological individualism, thereby overlooking the potential importance of social and welfare policies to tackle the population-level determinants of suicide. Using jurisdictional and temporal variations in social policies and patterns of suicide, this dissertation contributes to the literature by providing a summary of the current knowledge base of socioeconomic inequality in suicide and suicidal behaviour, identifying the knowledge gaps and future research questions, and adding novel evidence on the impacts of individual social policy and aggregate welfare generosity on suicide mortality and its inequality. In Chapter Two, consists of a scoping review of studies addressing socioeconomic inequalities in suicide and suicidal behaviour or the relationship between socioeconomic positions and different outcomes of suicidal behaviour in high-income countries with quality data. The literature is summarized to map the findings on the socioeconomic inequity in suicidal behaviour. The chapter concludes with an assessment of gaps in the current knowledge base and suggests a future research agenda. In Chapter Three, I examined whether relative welfare generosity in Canadian provinces is associated with overall suicide mortality and employment-based inequalities in suicide mortality by exploiting the provincial differences within Canada. In Chapter Four, I investigated the effects of two recent social pension reforms targeting older adults—Basic Old Age Pension (BOAP) and Basic Pension (BP)—implemented in South Korea on suicide mortality. Taken together, the findings of the dissertation contribute to the existing literature by mapping the relevant literature, identifying research gaps about socioeconomic inequalities in suicide, and suicidal behaviour, and examining the roles of social policy as a moderator of socioeconomic inequalities in suicide. / Dissertation / Doctor of Philosophy (PhD) / There is substantial evidence that suicide and suicidal behaviour are disproportionately observed among those with lower socioeconomic positions. Prior literature suggests that policy measures tackling severe socioeconomic deprivation may have impacts on reducing health gaps. However, little research is conducted to examine what effects can be brought by social and welfare policies on suicidal behaviour. This dissertation contains three studies on socioeconomic inequality in suicide and suicidal behaviour and examines the impacts of socioeconomic policies and welfare generosity that may tackle inequality. The overarching aim of the dissertation is to advance our understandings of socioeconomic inequality in suicide and suicidal behaviour by providing a systematic analysis of socioeconomic inequality in suicide and suicidal behaviour and roles of social policy and welfare generosity on suicide and suicide inequality. The dissertation contributes to the literature by mapping the relevant literature, identifying research gaps about socioeconomic inequalities in suicide, and suicidal behaviour and demonstrate novel findings about the roles of social policy.