This study was carried out to find out the effects of instructional resources on the academic achievement of secondary school students. The study is descriptive in nature and it adopted a survey design. Stratified random sampling technique was used for the selection. This therefore gives 29.8 respondents from teachers and 251.2 students making a total of 281 respondents. Teachers and students in the sampled schools were administered, an investigator–constructed questionnaire. Two research questions were raised for the study. Data collected were analyzed using simple percentages. The findings showed that instructional resources play a significant role in enhancing performance of students in schools. Furthermore, the results revealed that schools with adequate quality of teachers and enough instructional material resources showed superiority in academic achievements test than schools without adequate teacher quality and instructional material resources. As seen in the findings from this research, it could be easily concluded that the main reason for lack of proper use of instructional materials in the secondary schools is the lack of users’ education. The study therefore concludes that if authorities and staff should take this up as an urgent responsibility to build the expected capacity by orientating the users of the available instructional materials properly, improper use of available instructional materials will be curbed in Nigerian especially in the secondary schools setting.