In three chapters, I focus on how, and which, policy parameters of Canada’s public pension system affect seniors’ labour supply decisions. First, I study seniors’ labour supply responses to a series of reforms in 2012 and 2013 that incentivized many pensioners to extend their working lives; second, I assess how and whether receipt of public pension benefits affects seniors’ retirement timing differentially for those with different past earnings at ages 50-53; and, finally, I investigate older immigrants’ retirement and pension claiming decisions and how these decisions are impacted by permanent residency requirements for benefit eligibility. My analyses were carried out using income-tax and related panel data from the Longitudinal Administrative Databank (LAD), a 20% sample of taxpayers spanning the years 1982-2019 at the time of writing. In addition to detailed income-tax information, it contains information on receipt of non-taxable transfer income. / Dissertation / Candidate in Philosophy