This study was undertaken to assess quality control measures in terms of school supervision on teachers’ job performance in public primary schools in Calabar Educational Zone of Cross River State, Nigeria. One null hypothesis was formulated to guide the study. The sample consisted of four hundred and fifty-nine (459) teachers and one thousand, eight hundred and thirty-six (1,836) pupils selected from primary six and JSS2 class. Two instruments were designed for the collection of data. These were Quality Control Measures Questionnaire (QCMQ) and Teachers’ Job Performance Questionnaire (TJPQ). Pearson reliability was 0.80 and 0.71 respectively. The data collected were subjected to statistical analysis using One-way Analysis of Variance (ANOVA) and Fisher’s protected t-test. The hypothesis was tested at 0.05level of significance. Findings of the study showed that there was a significant influence of school supervision on teachers’ job performance. It was concluded that teachers’ job performance could be improved through school supervision. It was recommended among others, that regular school supervision should be undertaken to monitor teachers.