This document summarizes a presentation on license interoperability for public sector information (PSI) reuse. It discusses how open source software and open content have progressed toward interoperable licensing over the past 25+ years, but challenges remain including incompatible copyleft licenses and a proliferation of custom licenses. Key initiatives like Creative Commons and Open Knowledge Foundation are working to address these issues and promote consensus licensing principles that only include open terms to facilitate greater interoperability and reuse of PSI. Upcoming milestones that could impact licensing include events focused on the EU's digital agenda and open knowledge.