BACKGROUND: Perinatal distress is a significant public health problem that adversely impacts the individual and their family. The primary objective of this systematic review and meta-analysis was to identify factors that partners can modify to protect each other from developing perinatal depression and anxiety. METHOD: In accordance with the PRISMA statement, we reviewed the risk and protective factors associated with perinatal depression and anxiety symptoms that partners can potentially modify without professional assistance (PROSPERO reference CRD42014007524). Participants were new or expectant parents aged 16 years or older. The partner factors were sub-grouped into themes (e.g., instrumental support) based on a content analysis of the scale items and measure descriptions. A series of meta-analyses were conducted to estimate the pooled effect sizes of associations. RESULTS: We included 120 publications, reporting 245 associations with depression and 44 with anxiety. Partner factors with sound evidence that they protect against both perinatal depression and anxiety are: emotional closeness and global support. Partner factors with a sound evidence base for depression only are communication, conflict, emotional and instrumental support, and relationship satisfaction. LIMITATIONS: This review is limited by the lack of generalizability to single parents and the inability to systematically review moderators and mediators, or control for baseline symptoms. CONCLUSION: The findings suggest that future prevention programs targeting perinatal depression and anxiety should aim to enhance relationship satisfaction, communication, and emotional closeness, facilitate instrumental and emotional support, and minimize conflict between partners.