Background: There is limited data on the prevalence of child and adolescent mental health disorders (CAMHD) in Ghana. Recent reports suggest a decline in academic achievement in basic education. This paper sought to determine the prevalence of CAMHD in Ghanaian primary school children and to draw correlates with academic achievement.Methods: We conducted a pilot cross-sectional survey of 303 grade 3 pupils aged 7-15 years in the city of Kumasi. The Child Behaviour Checklist (CBCL) and Kiddie-Schedule for Affective Disorders and Schizophrenia (K-SADS-PL) were used to assess for CAMHD in 2016, and data on performance in examinations over the prior academic year were analysed.Results: Overall, current prevalence of CAMHD was 7.25%, with depressive disorder = 1.31%, anxiety disorders = 1%, attention deficit hyperactivity disorder (ADHD) = 1.64%, conduct disorder = 1.97%, and intellectual disability = 1%. Co-morbid disorders, such as seizure disorder (1%), were also noted. There was a greater prevalence of CAMHD in public schools (11.6%) compared to private schools (0.7%), with p < 0.001. Even when adjusted for other factors, children with CAMHD had a lower average academic score by 10.5 units (p < 0.001). Thus, having a dual diagnosis was most predictive of academic underachievement.Conclusions: The results of this study document the prevalence of CAMHD in Ghana for the first time and shows correlates with academic underachievement.