Purpose: The purpose of this study was to investigate whether there are elevated symptoms of anxiety or depression in children and adolescents (aged 2-18 years) who stutter, and to identify potential moderators of increased symptom severity. Method: We conducted a preregistered systematic review of databases and gray literature; 13 articles met criteria for inclusion. A meta-analysis using robust variance estimation was conducted with 11 cohort studies comparing symptoms of anxiety in children and adolescents who do and do not stutter. Twenty-six effect sizes from 11 studies contributed to the summary effect size for anxiety symptoms (851 participants). Meta-analysis of depression outcomes was not possible due to the small number of studies. Results: The summary effect size indicates that children and adolescents who stutter present with increased anxiety symptoms (g = 0.42) compared with nonstuttering peers. There were insufficient studies to robustly analyze depression symptoms, and qualitative review is provided. No significant between-groups differences were reported in any of the depression studies. Conclusions: Preliminary evidence indicates elevated symptoms of anxiety in some children and adolescents who stutter relative to peers. There was a tendency toward higher depression scores in this population, although reported between-groups differences did not reach statistical significance. These findings require replication in larger, preferably longitudinal studies that consider factors that may moderate risk. Nevertheless, our findings highlight a need for careful monitoring of mental health and well-being in young people who stutter.