Therapeutic combinations of immunoconjugates that bind to FOLR1 (e.g., IMGN853) with anti-PD-1 antibodies or antigen-binding fragments thereof (e.g., pembrolizumab) are provided. Methods of administering the combinations to treat cancers, e.g., ovarian, peritoneal, or fallopian tube cancers, with greater clinical efficacy and/or decreased toxicity are also provided.