Purpose <p>The psychiatric length of stay (LOS) in community-based hospital facilities in sub-Saharan Africa reflects the quality of service delivery and the presence of resource challenges. This study aimed to determine the average LOS and identify factors associated with prolonged LOS in the psychiatric unit of a Ghanaian teaching hospital.</p> Methods <p>The study analysed 1143 hospital discharge records of psychiatric inpatients at Komfo Anokye Teaching Hospital Psychiatric Unit from January 2016 to October 2020. LOS greater than the median of 10 days was classified as prolonged. We performed multivariable logistic regression to determine factors associated with prolonged LOS.</p> Results <p>The mean LOS was 12 days, and the median LOS was 10 days. Bipolar and related disorders (aOR = 1.68 95% CI (1.28–2.21)), substance use disorders (aOR = 1.98 95% CI (1.19–3.30)), co-occurring mental health and substance use disorders (aOR = 2.30 95% CI (1.20–4.56)), and being discharged home directly (aOR = 1.91 95% CI (1.03–3.69)) was associated with a longer hospital stay, while suicide-related behaviour (aOR = 0.27 95% CI (0.09–0.72)) was associated with decreased odds of prolonged hospital stay.</p> Conclusion <p>Possible interventions to reduce the length of psychiatric stay in the general hospital setting include improving functional integration of mental health into primary care and implementing transitional treatment programmes like partial hospitalisation and intensive outpatient treatment programmes. Improving access to residential substance use treatment is another intervention that can help decrease the burden of prolonged psychiatric stays.</p>