This document summarizes the work of Creative Commons Netherlands in promoting openness in the public sector. Creative Commons Netherlands, supported by the Dutch ministry of culture, education and science since 2005, works to improve adoption of Creative Commons licenses through providing information and collaborating with institutional users like educational institutions, cultural heritage organizations, and the public sector. The document provides examples of Wikiwijs, an open educational platform launched by the Dutch ministry of education that uses a Creative Commons license, and Rijksoverheid.nl, the Dutch government's unified website that uses the Creative Commons Zero public domain dedication. It concludes with lessons learned around combining advocacy and research, relating policy objectives, and preparing implementers to address legal questions.