The study explored the issue of truancy and its effect on academic performance of senior secondary school science students in Bwari Area Council of FCT-Abuja. The study used descriptive survey research design. The population consisted of form masters in the selected secondary schools in Bwari Area council and a total of 120 form masters were selected from a total of 12 secondary schools and 10 form masters were picked from each of the schools. A structured questionnaire, Form Masters' Questionnaire on Truancy and Academic Achievement (FMQTAA), was used to gather the data. The instrument was expertly validated and the obtained data was analyzed through mean and standard deviation which were used to answer the research questions and Pearson Product-Moment Correlation was used for testing the hypotheses at level of 0.05 of significance. The results indicated that although science students of the senior secondary level were found to display truant behavior it was not a widespread practice among all students. The interrelationship between these was agreed. The respondents agreed some pupils deliberately went missing from school without authorization; arrived after classes and in some instances missed lessons in the subject of science even when in school. The results also showed a negative correlation between the proportion of pupils eligible for free school meals and their academic attainment scores, suggesting that the more pupils miss their school's morning service, the worse their academic attainment scores are. The research that was conducted found that being a persistent truant may be detrimental to the students' ability to learn science effectively and have detrimental effects on their learning. Enhanced monitoring and tracking of attendance by school leaders, regular counselling and mentoring of students from GWCF by school guidance counsellors, more parental participation in monitoring child attendance, and academic support by science teachers for students who are back after absence were all recommended.