It is generally believed that teachers are important both to student learning and achievement. Apart from teacher qualification and experience, some studies have shown that teacher gender may relate significantly to student achievement. The purpose of the study was to find out the following- (a) Does teacher gender significantly influence student academic achievement in English Language Arts at the junior secondary school level? (b). Does teacher gender significantly influence student academic achievement in Mathematics at the junior secondary school level? (c) Does teacher gender significantly influence student academic achievement in Biology at the junior secondary school level? Data was obtained from 570 students in seven junior secondary school students in South-East area of Nigeria. An analysis of data showed the following- In the English Language Arts area, and at the junior secondary school level, female students performed significantly higher than male students under a female teacher and male students performed better (but not statistically significant) under male teachers. In the area of Mathematics, female students performed significantly higher under male teachers. Based on the findings, recommendations were made on improving the teaching of English Language Arts, Mathematics and Integrated Science in Nigerian junior secondary schools.