This study investigates the Impact of Cognitive Conflict Instructional Model on Conceptual Change and Academic Performance in Genetics among Senior Secondary School III Biology students. A Quasi-experimental pretest and posttest research design was used for the study which featured two groups (Experimental and Control group). The experimental group was exposed to cognitive conflict instructional model (CCIM) while the control group was taught using lecture method. Sample sizes of 199 students selected from four secondary schools in Potiskum, Yobe State were used as the study sample, drawn from a population of 16 single sex (that is, either male or female) schools with a total of 1021 students. The Four schools randomly selected, were selected after matching them, to find their academic equivalence. The Instruments developed; Genetics Performance Test (GPT) and Genetics Concept Evaluation (GCE) with a reliability coefficient of 0.78 and 0.79 were used to collect data for pretest, posttest and gender equivalent. Four research questions and four null hypotheses guided the study.One of the research questions was: what is the difference in the mean conceptual change score of secondary school students taught genetics concept using cognitive conflict instructional model and those taught using lecture method?. One of the null hypothesis was : there is no significant difference between the mean conceptual change score among secondary school biology students in genetics taught using cognitive conflict instructional model and those taught using lecture method. The data collected were analyzed using t-test Statistic and Chi-square test at significance level of P≤0.05. Results indicated that; (i) the experimental group performed significantly better than the control group in their academic performance, showing there is a significant difference. (ii) the model was found to have promoted the experimental group students' scientific Conception (that is their level of conceptual change)as there was a significant shift of students from alternative or no conception to sound conception after treatment with CCIM. (iii) The treatment has no significant effect on gender which implied that the model is gender friendly. Based on these findings, it was recommended that;there is a need for training and retraining of science teachers towards effective use of CCIM in the teaching of science at SSS level as it promotes scientific thinking.