Introduction Policymakers may sometimes be reluctant to develop policies for smoke-free outdoor spaces due to concerns about public reaction. In this study, we investigated the support for a smoke-free campus before and after the campus of a Dutch research institute became smoke-free. Methods We conducted two surveys among employees to measure the level of support for a smoke-free campus. The first survey (n=129) was conducted 3 months before and the second 13 months after the implementation of a smokefree campus policy (n=134). Results More employees supported the smoke-free campus after (82.1%) than before (64.3%) implementation (OR=2.55; 95% CI: 1.39–4.70; p=0.003). In addition, more employees (75.4%) employees believed it is important to have a smoke-free campus than was the situation before (56.6%) the implementation (OR=2.28; 95% CI: 1.31–3.97; p=0.004). Conclusions This case study adds to the knowledge that support for a smokefree campus increases after implementation of a smoke-free policy. This may encourage other organizations or local governments to create policies for smokefree outdoor spaces.