Background: Children and adolescents with language problems have poorer mental health compared with their non-language impaired peers. Less is known about mental health in adults with a history of language problems. This paper presents a systematic review and meta-analysis that addresses this gap in the literature. Specifically, it summarises the results from studies examining anxiety and depression in adults (aged 18 years and over) who were identified with language impairments or problems earlier in development. Methods & Procedures: Five electronic databases (PsycINFO, ERIC, CINAHL, EMBASE and PubMed) were searched for studies comparing anxiety and/or depression in a sample of adults with and without a history of language problems. Nine studies were found that met the inclusion criteria. From each, an odds ratio (OR) was computed measuring the relationship between childhood language problems and anxiety or depression in adulthood. The OR was computed so values > 1 which indicated anxiety/depression were associated with a history of language problems. ORs were averaged using multilevel random effects meta-analysis. Outcomes & Results: Averaging the study's findings across both anxiety and depression outcomes, we found that a history of childhood language problems was associated with poorer mental health in adulthood (OR = 1.79, p = 0.004). The association for anxiety was also significant (OR = 1.80, p = 0.012) and close to statistical significance for depression (OR = 1.60, p = 0.054). Conclusions & Implications: This review reveals that adults with a history of language problems are more likely to experience poorer mental health outcomes compared with controls. These findings demonstrate childhood language problems affect not only communication but also mental health and well-being in the long term.