This research work was conducted to determine the effects of class-size and field trip on academic performance of agricultural science students in senior secondary schools in Kaduna state. The study raised four (4) specific objectives, research questions and null hypotheses each to guide the study. With and without quasi-experimental design was adopted for the study. The population for the study was 12,370 SS III students of agricultural science. Purposively sampling technique was employed to select 102 agricultural science students in Government Secondary School, Sabon Tasha. The instrument used for data collection was a multiple-choice test consisting of a 20-item Achievement Test in Agricultural Science (ATAS). Mean and standard deviation were used to answer all the research questions, while T-test statistics was used to test the null hypotheses at 0.05 alpha value of significance. Null hypotheses 1 and 2 were rejected because their T-values were less than the alpha value (p<0.05). Null hypothesis 3 and 4 were accepted and retained because their T-values were greater than the alpha value (p>0.05). The analysis of the findings revealed that field trip and class size had significant effects on the academic performance of agricultural science students and no significant differences in the academic performance of male and female agricultural science students in a normal class size and those taken to field trip. It was concluded that, normal class size was effective in teaching and learning of agricultural science. Field trip broadens and exposed students to real life context in agriculture. It was also concluded that normal class size and field trip do not affect gender academic performance of agricultural science students in senior secondary schools. It was recommended that government should build more classrooms with adequate facilities of agricultural science and curriculum planners should make sure that field trip is made compulsory and relevant in agricultural science curriculum among other recommendations.