Knowledge sharing during unplanned face-to-face meetings between employees is indispensable for innovation-based organizations. Spatial design of office buildings has been proven to influence the number of meetings dyads have at work, but research on the behavior during such meetings remains scarce. This article analyzes how several spatial variables relate to employee behavior during such meetings (joint activities, location, intentionality, and issues addressed). A 1-week diary of 138 employees from one research organization provided data on 918 knowledge-sharing meetings. Analysis of the building layout showed that behavior is particularly different at a very local level within the building. Chi-square tests showed that inter-visibility and proximity are most strongly associated with where knowledge was shared, while sharing a room and overhearing related significantly to how knowledge was shared.