Background The prevalence of language disorder in youth offenders far exceeds rates reported in community samples. Youth involved in the justice system are also at increased risk of a range of psychiatric disorders, including internalizing mental health problems (i.e., anxiety, depression). However, the frequency with which these co‐occur in this population is not known. Understanding the co‐occurrence of language disorder with anxiety and depression in youth offenders may contribute to more coordinated and targeted support for these vulnerable youth. Aims To explore the co‐occurrence of language disorder and anxiety and depression in youth offenders. Methods & Procedures A systematic literature search of six databases (CINAHL, ERIC, Medline, PyscINFO, PubMED, Scopus) was conducted (September 2021) using key search terms relevant to the systematic review question. Study inclusion criteria were: (1) original research published in English; (2) youth up to 21 years of age involved in the justice system; and (3) reported outcomes on language and anxiety and/or depression. All included studies were appraised using the Joanna Briggs Critical Appraisal tool checklist relevant to study design. Due to the heterogeneity of included studies, data synthesis was narrative. Main Contribution Eight studies met the eligibility criteria. A range of measures was used to assess language abilities across samples. Only two studies directly addressed the relationship between language disorder and internalizing mental health problems; both found no significant correlation. Conclusions & Implications Although the results did not support a significant relationship between language disorder and internalizing mental health problems in youth offenders, the two appear to occur comorbidly as evidenced by heightened rates of both in the included samples. This review highlights the need for more robust studies aimed to better understand this relationship. Stronger evidence may contribute to increased collaborative speech pathology and psychology services which might increase youth offenders’ accessibility and engagement in intervention programmes (e.g., cognitive–behaviour therapy; interpersonal skills training; individual counselling). WHAT THIS PAPER ADDS What is already known on this subject The markedly high rates of language disorder in youth involved in the justice system have been widely reported. It is also known that externalizing mental health problems often bring youth in contact with the justice system. Though there is some information about the prevalence of internalizing mental health problems in this population, the co‐occurrence of language disorder and internalizing mental health problems has not been examined as widely. What this study adds to existing knowledge This study aimed to identify the frequency of co‐occurrence of language disorder and anxiety and/or depression in youth offenders. Although the results did not support a significant relationship between language disorder and internalizing mental health proble...