ABSTRACT Teachers are the core influential aspect in students’ learning and achievement. This study was conducted in the Kwabre Municipal in the Ashanti region. The purpose of the study was to find the effect of teaching unspecialized subject on students’ academic performance. The study employed descriptive and inferential statistics. The study was conducted with a sample of 60 teachers. Primary data was collected from the Municipal through Selfadministering method for the study. The Reliability test using Cronbach's alpha had (α = 0.768) for questionnaire. Findings from the study revealed that the factors accounting for teaching unspecialized subjects are; Laissez- Faire Attitude, A natural loss of Teachers and Non-existence of accurate collected workforce data. The principal challenge of teaching unspecialized subjects in School is “Teacher limits interaction by rushing through topics”. There is weak negative correlation (R = - 0.167and R2 = 0.027, p > 0.05) between teaching unspecialized subject and student academic performance. The study concludes that there is negative impact of teaching unspecialized subject on students’ academic performance. The study Recommend that educational directors in the Municipal should ensure that the required number of teachers are employed and also restrained from assigning teachers to teach in the Municipal with Laissez- Faire Attitude