Many people now work in office-based jobs, which can be highly sedentary. As high levels of sitting time are associated with increased mortality and chronic disease risk, there has been increasing interest in effective strategies to reduce sitting in workplaces. The spatial design of office environments may potentially influence sitting and other workplace behaviours. For example, people may sit more if they do not have other places to visit within the workplace, such as discussion spaces and meeting rooms. Office spatial design may also influence the frequency of informal face-to-face interactions with work colleagues by providing suitable places for conversations. Face-to-face interactions are considered important for improving the performance of knowledge-based workplaces. Given that workplace sedentary behaviour and face-to-face interactions may be associated with workplace health and productivity outcomes, identifying modifiable office spatial factors that can influence these behaviours can inform better office design. We conducted a systematic review to synthesise the evidence on links between office spatial design factors with workplace sitting and informal face-to-face interactions. What did we do? We searched six databases in November 2019 (before the COVID-19 pandemic began) for peer-reviewed articles that examined associations of office spatial design attributes with sitting or face-to-face interactions. We excluded…