Objectives: Meditation interventions typically show small to moderate effects on health and well-being, but we know little about how these effects vary across individuals. This meta-analytic study investigates the relationship between baseline participant characteristics and the outcomes of meditation. Methods: A systematic search yielded 51 eligible studies with 7782 participants. A combination of subgroup analyses and meta-regression based on the random-effects model were used. Results: We found that a higher baseline level of psychopathology or depression was associated with deterioration in mental health after a meditation intervention. On the other hand, participants with higher scores on interpersonal variables, motivation, medical conditions, and mindfulness showed higher levels of positive meditation outcomes. Higher well-being and stress were simultaneously associated with moderate increases in negative and positive meditation outcomes. Participant demographics, psychological traits, self-concept, and length of meditation practice did not significantly influence the response to meditation. Conclusions: Overall, we found that meditation interventions affect participants differently, and identified some of the individual characteristics that should be considered when using meditation interventions.