Body dissatisfaction is a global public health concern. Self-injurious thoughts and behaviours (SITB), including suicidal ideation, suicide attempts and non-suicidal self-injury (NSSI), have been documented as potentially significant correlates of body dissatisfaction. However, prior findings regarding associations between body dissatisfaction and SITB have been somewhat inconsistent. Therefore, this meta-analysis was conducted to determine the nature and strength of such associations in both clinical and non-clinical samples. A literature search identified 83 relevant articles and extracted 234 effect sizes. Using a three-level random-effects model, mean effect sizes (r values) for relationships between body dissatisfaction and suicidal ideation, suicide attempts, and NSSI in clinical samples were 0.29 (95% CI, 0.22–0.37), 0.16 (95% CI, 0.13–0.20) and 0.26 (95% CI, 0.19–0.34), respectively. In non-clinical samples, these values were 0.22 (95% CI, 0.16–0.28), 0.24 (95% CI, 0.17–0.30) and 0.22 (95% CI, 0.15–0.29), respectively. Several study features (e.g., participant age, geographic region and instrument validity) emerged as significant moderators. This meta-analysis provides robust support for body dissatisfaction as a significant correlate of SITB across clinical and non-clinical samples in addition to identifying study characteristics that contribute to effect size variability. Implications are discussed for SITB research, prevention and intervention.