Contesting Austerity compares the contentious responses to austerity in Portugal and Spain between 2008 and 2015. While in Spain a sustained wave of mobilisation lasted for three years and led to a transformation of the party system, in Portugal social movements mobilised only in specific instances, trade unions dominated protest and institutional change was limited. Contesting Austerity shows that trajectories and outcomes in these countries are linked to the nature and configurations of the players in the mobilisation process.