This study identified the effect of truancy on academic performance of secondary school students in Maiha Local Government Area, Adamawa State. The study was guided by four research questions. The study used descriptive research design method. The sample size of the study was 400. Three research instruments were used for this study, namely; academic records of students’ performance, attendance register and questionnaire titled “Effect of truancy on Academic Achievement of Students” (ITAAS) and was validated by three experts, two experts in Guidance and Counselling and one expert in Tests and Measurement from Faculty of Education, Adamawa State University, Mubi. The reliability was carried out using test-retest reliability method and the reliability co-efficient was 0.83. Data were analyzed using frequency counts, percentages, t-test and chi-square. The findings of the study showed that there was a significant relationship between truancy and academic performance of students; and there was no significant difference between academic performance of male and female truants. In conclusion, truancy has serious effect on students learning and their general academic performance. It was recommended that parents should guide their children into the right path and be a good model to their children.