A meta‐analysis of 40 findings from 36 studies (N= 4,952) provided substantial overall support for the proposition that depressive symptoms and mood are contagious. Contagion appeared most pronounced in studies of depressive symptoms (vs. depressive mood). Contagion of depressive mood appears to depend on methodological approach, with strongest to weakest results in the following order: transcript studies, audio/ videotape studies, studies using actual strangers, studies using actual friends/acquaintances, and confederate studies. Contagion of depressed mood/symptoms held across combinations of target × respondent gender. There was very tentative evidence that contagion was specific to depressive versus other symptom/moods. Based in part on our meta‐analytic findings, we summarize possible explanations of the phenomenon from cognitive, behavioral, and interpersonal viewpoints and elucidate some clinical implications.