This study was carried out to determine the effects of instructional resources on students' academic performance in agricultural science in senior secondary schools in Kaduna State, Nigeria. The desire to embark on the research study therefore, stemmed from the fact that inadequate and lack of use of instructional resources was seen as major factors behind the poor academic performance of students in Kaduna State. The objective for this study was therefore to determine the effects of instructional resources on students' academic performance in agricultural science in senior secondary schools in Kaduna State, Nigeria. Four specific objectives, four research questions and four null hypotheses were formulated to guide the study. The population for the study comprised of 14,241 secondary school students in Kaduna state who offer agricultural science. Quasi experimental design was adopted for the study. Being an experimental design, the treatment was given to students of GSSManchok purposively selected. The students were used as intact classes made up of 45 male and 45 female students as experimental groups A and B. The control group C was constituted and taught using the traditional (lecture) method while the experimental groups A and B were taught using the charts and real objects respectively. The groups were givenpre testand post test accordingly. Instrument for data collection was Agricultural Science Achievement Test (ASAT). The period of data collection lasted for six weeks. Data collected were analyzed using frequency tables, percentages, means and standard deviation, while t-test statistics was used to test the null hypotheses at significant level of 0.05. The findings among others showed that the use of charts had more significant effect, but however show no significant difference between the performance of male and female students. This study concludes that, the use of instructional resources significantly affects students' academic performance in agricultural science which increased students' retention ability. Based on the findings it was recommended that: schools inspectors should ensure that teachers are encouraged to improvise and use instructional resources in teaching agricultural science and other similar subjects.