It is evidence based conclusion that students' classroom participation makes them more motivated, supports their learning, improves their communication and promotes higher order thinking skills. The current study was an intention to investigate the current level of secondary school students' classroom participation and to identify the underlying factors that contribute to it. The study was conducted on 9th and 10th grade students, randomly selected from 19 boys' and 21 girls' government high schools in Lahore city. Sampling process consisted of two stages. In the first stage, 10% sample size was calculated which led to random selection of 4 schools, two from each cohort. At second stage, 500 students were purposively selected from 1689 students, 250 from each cohort. A self-report questionnaire (FBCPS) was used to collect data. Response rate was 70%. Simple descriptive and inferential statistics were used to analyze the data. The study concluded that students exhibit significant level of classroom participation. Further boys participated more in the class as compare to girls, while internal and external factors behind their classroom participation were same, although the extent to which they influence was different. Girls were influenced by motivation in their classroom participation as compared to boys. Boys' participated more due to high self-esteem. Teachers, parents and peers and curriculum are important external factors which supported boys classroom participation more than girls who in turn more influenced by classroom environment.