The study is designed to examine the influence of mother tongue on Students performance in English language in Junior School Certificate Examination. The study investigated if mother tongue is solely the cause of the students’ woeful performance in English Language in Junior School certificate Examination or if there are other complementing factors. The subjects for the study were one hundred male and female SSI students drawn from various government schools in western Nigeria. Using simple percentage descriptive statistic, the research questions that were raised analysed. The findings reveal that mother tongue influences the students’ poor performance in English language in Junior School Certificate examination and that there are other factors contributing to students’ poor performance in English language. These other factors are poor method of teaching, lack of textbooks, language background and lack of professional growth and development of teachers. Measures that could be taken to enhance students’ achievement in every aspect of English language are suggested also. The respondents’ age ranged between 10.52 and 15.17. The participants were those who have sat for the Junior Secondary School Certificate examination. They were randomly selected across diverse religious and socio-economic background.