Multiunit housing (MUH) residents are susceptible to secondhand smoke (SHS) exposure, which can transfer between living units. This review summarises existing scientific literature relevant to smoke-free MUH, discusses knowledge gaps and provides recommendations for future research to inform public health action.We conducted a systematic search of peer-reviewed articles using three databases: EBSCOhost CINAHL, PubMed and Web of Science.Article titles, abstracts and text were reviewed to ascertain three inclusion criteria: (1) English language; (2) conducted in the USA; (3) reported on baseline data, development, implementation or evaluation of smoke-free MUH.We used a multistep process to identify eligible articles: (1) two reviewers separately evaluated article titles; (2) two reviewers separately evaluated abstracts and (3) one reviewer read each article and determined inclusion eligibility.We identified and included 35 articles published during 2001-2014, grouped based on broad themes: MUH resident (n=16); MUH operator (n=6); environmental monitoring and biomarkers (n=9); economic (n=2); legal (n=3); and implementation process and policy impact (n=8). Studies with multiple themes were included in all relevant groups.Existing literature has focused on self-reported, cross-sectional studies of MUH residents and operators; some studies of environmental markers, biomarkers and economic indicators have also been conducted. Future research on smoke-free MUH policy compliance and enforcement, and on the impact of these policies on smoking behaviours and health outcomes, could further inform public health planning, policy and practice. Despite these gaps, the current literature provides sufficient evidence for action to eliminate SHS exposure in MUH.