This paper provides a panoramic and comparative analysis of the legislation passed by the Autonomous Communities to tackle climate change. The Paris Agreement gives them a leading role, together with other actors, as subnational entities to face and achieve the challenges posed by climate change mitigation and adaptation. At the time of writing, only three autonomous communities have approved legislative instruments to mitigate and adapt to climate change. These are Catalonia, Andalusia, and the Balearic Islands. However, other regions have approved strategies and policies for the same purpose, and some have begun the process of approving the relevant legislation. In this paper we study the objectives to mitigate and adapt to climate change set out in these laws, the legal instruments they prescribe to achieve them, and their effective implementation and development. [ABSTRACT FROM AUTHOR]