The subsidiarity principle in innovation policy for societal challenges (published: 2020)This article claims that innovation policies aimed to solve societal challenges, such as climate change or aging, are best pursued at subnational levels given the contested nature of problem identification and the contextual nature of problem-solving. Regional innovation policy, then, should formulate concrete societal goals tailored to the local context, while the transnational context promotes inter-regional learning and provides the complementary policies in the realms of basic research, regulation and taxation.