In this thesis, I consider the following research question: What explains Canada s withdrawal from the Kyoto Protocol? Canada s withdrawal came as a surprise to many, for two reasons: Firstly, Canada has traditionally been viewed as a global leader in international climate cooperation. Secondly, the announcement of the withdrawal in December 2011 meant that it would take effect in December 2012, only two weeks before Kyoto s first commitment period ended. In this qualitative case study I seek answers to my research question at three levels &ndash; the international, the national and the sub-national. Each level draws on a different theoretical framework and points to different explanatory factors. I begin by applying the unitary actor model, then move to the theory of two-level games, and finally analyze the sub-national level through a combination of two-level games and a theory of provincial influence on Canadian federal climate policy. I find that a combination of drastically increasing compliance costs, a change in government, and sharp resistance from oil-abundant provinces against the implementation of Kyoto, were the main causes of the withdrawal.