Socioeconomic status (SES) is a robust correlate of mental health, and emerging research indicates that life course trajectories of SES (i.e., social mobility) may be more predictive for health outcomes than point-in-time SES assessments. This paper presents five primary meta-analyses to determine how mental health differs between social mobility groups. We conducted a systematic review of PsycINFO, Web of Science, and PubMed for studies of social mobility and mental health. We used random-effects multilevel meta-analyses to compare mental health problems between individuals who experienced upward mobility, downward mobility, stable high SES, and stable low SES. We included data from 21 studies and 157,763 unique participants yielding 105 effect sizes. Upwardly mobile participants experienced more mental health problems than stable high SES participants (d = 0.11), fewer mental health problems than stable low SES participants (d = -0.24), and fewer mental health problems than downwardly mobile participants (d = -0.17). Downwardly mobile individuals experienced more mental health problems than stable high SES participants (d = 0.26) and fewer mental health problems than stable low SES participants (d = -0.10). Subgroup analyses revealed that the magnitude of effects did not differ by continent of study, type of generational mobility (intergenerational vs. intragenerational), or SES indicator. Meta-regressions with continuous moderators (age, gender, race, study quality) were also non-significant. Taken together, these results indicate that both upwardly and downwardly mobile individuals experience more mental health problems than those who are persistently advantaged, and they both experience fewer mental health problems than those who are persistently disadvantaged. Our findings suggest that while current SES has a stronger association with adult mental health than childhood SES, it is important to also consider the impact of early life and prior generation SES to account for lingering effects of early disadvantage.