Vaping prevention messages are widely used to communicate the health harms and addiction risks of vaping and discourage vaping among adolescents and young adults. We conducted a meta-analysis of experimental studies to examine the effects of these messages and to understand their theoretical mechanisms. Systematic, comprehensive searches generated 4,451 references, among which 12 studies (cumulative N = 6,622) met inclusion criteria for the meta-analysis. Across these studies, a total of 35 different vaping-related outcomes were measured, and 14 outcomes assessed in two or more independent samples were meta-analyzed. Results showed that compared to control, exposure to vaping prevention messages led to higher vaping risk perceptions, including harm perceptions (d = 0.30, p < .001), perceived likelihood of harm (d = 0.23, p < .001), perceived relative harm (d = 0.14, p = .036), addiction perceptions (d = 0.39, p < .001), perceived likelihood of addiction (d = 0.22, p < .001), and perceived relative addiction (d = 0.33, p = .015). Also, compared to control, exposure to vaping prevention messages led to more vaping knowledge (d = 0.37, p < .001), lower intentions to vape (d = -0.09, p = .022), and higher perceived message effectiveness (message perceptions; d = 0.57, p < .001; effects perceptions; d = 0.55, p < .001). Findings suggest vaping prevention messages have an impact, yet may operate through different theoretical mechanisms than cigarette pack warnings.