We study the broken windows theory with a field experiment in a shared area of a workplace in academia (department common room). We explore academics' and postgraduate students' behaviour under an order condition (clean environment) and a disorder condition (messy environment). We find strong support that signs of disorderly behaviour triggers littering. In the disorder treatment 59% of the subjects litter compared to 18% in the order condition. The results remain robust when controlling compared to previous studies for a large set of factors in a multivariate analysis. When academic staff members and postgraduate students observe that others violated the social norm of keeping the common room clean the probability of littering increases ceteris paribus by around 40 percent.