Malnutrition is one of the major problems facing the developing countries, especially among children. It is estimated that, 28% of children under the age of five are stunted whilst 14% are underweight in Ghana. Minister of Food and Agriculture in 2004 asserted that the Intelligent Quotient (IQ) of Ghanaian children has generally reduced due to poor dietary composition of their food coupled with little attention paid to good nutrition and that the nation is likely to suffer the consequences of unintelligent generation. It is against this background that this study was conducted to assess the nutritional status of Junior High School (JHS) students in the Mfantseman Municipality in the Central Region of Ghana with the objectives of estimating the body mass index (BMI) of the students through anthropometric measurements and use the BMI to determine their nutritional status as well as finding out factors contributing to their nutritional status. The study used purposive, convenient and random sampling techniques to select 7320 school children. Data was collected on the students' age, height and weight. The Body Mass Index (BMI) for age was calculated and compared with the 2007 WHO reference to identify their nutritional status. The study revealed that overall prevalence of malnutrition in the community was high with 25.9% of the children being overweight, 5.5 and 5.8% been lean or severely lean while 39.0% were normal. The incidence of malnutrition was prevalent among boys than girls. The high incidence of malnutrition may be attributed to improper dietary habits, unawareness of balanced diet, poor prenatal nutrition and low family income.