Field trip’s effect on students’ academic performance in secondary school Biology, Makurdi, Benue State was studied using a pretest post-test quasi experimental control research design. Two research questions and two hypotheses guided the study. The population comprised 1,989 SS2 Biology students in the 22 government secondary schools. A sample of 67 SS2 students was selected through multistage sampling from two co-educational schools. Intact classes were randomly assigned to experimental group taught with field trip instruction (n=32) and control group taught with Teacher Demonstration Method (n=35). Data were collected using a 50-item Biology Performance Test (BPT) with reliability coefficient of 0.82. Two research questions were answered using mean and standard deviation, while two null hypotheses were tested at 0.05 level of significance using ANCOVA. Findings revealed that students taught Biology using field trip instruction had a higher mean gain score of 17.97 compared to 0.75 for those taught with Teacher Demonstration Method. ANCOVA showed a statistically significant difference in performance, F (1, 64) = 185.617, p < .05, with a large effect size of .744. Regarding gender, female students had a mean gain of 18.55 while males had 15.67, but ANCOVA showed no significant difference, F (1, 31) = 1.849, p = .184 > .05. It was concluded that field trip instruction significantly enhances students’ academic performance in Biology and is effective for both male and female students. Therefore, it was recommended that Biology teachers should integrate field trips into instruction, and relevant authorities should provide necessary support for its implementation.