Psychiatric facilities are often criticised of being poorly designed which may contribute to violent incidents and patients’ complaints of feeling bored and lacking meaningful interactions with peers and staff. There is a lack of understanding how to design environments for staff, patients and visitors to engage in positive social interactions (e.g. conversation, sharing, peer support). We conducted a systematic literature review on which architectural typologies and design solutions facilitate helpful social interactions between users of psychiatric facilities. Several interventions were identified such as choosing a community location; building smaller (up to 20 beds) homelike and well integrated facilities with single/double bedrooms and wide range of communal areas; provision of open nursing stations; ensuring good balance between private and shared spaces for patients and staff; and specific interior design interventions such as arranging furniture in small, flexible groupings, introduction of plants on wards, and installing private conversation booths. These interventions range from simple and non-costly to very complex ones. The evidence should inform the design of new hospitals and the retrofitting of existing ones.