Sleep has been considered crucial for recovery, but little is known about the specific associations between the work–family interface and sleep quality. Based on COR theory, the goal of this study is to examine the moderating role of sleep quality on the relationship between work–home interaction (i.e. negative work–home interaction, negative home–work interaction, positive work–home interaction, and positive home–work interaction) and psychological strain. A total of 273 ambulance workers from Spain participated in the study. Multiple regression analyses revealed that sleep quality moderated the relationship between negative and positive home–work interaction and psychological strain. Findings are discussed in terms of their theoretical and practical implications.