Inadequate physical activity (PA) levels are reported in Indian youth, with lowest levels among adolescents, particularly girls. We aimed to identify barriers to and enablers of PA among school children in New Delhi and examine potential differences by gender and school type (government vs. private). A total of 174 students (private school students = 88, 47% girls; government school students = 86, 48% girls) aged 12 to 16 years from two Delhi schools participated in 16 focus group discussions (FGDs) conducted by bilingual moderators. We conducted FGDs separately for girls and boys, for students in Grades VIII and IX, and for private and government schools. We conducted FGDs among government school students in Hindi and translated the transcriptions to English for analysis. We coded transcriptions using a combination of inductive and deductive approaches, guided by the "youth physical activity promotion model." We identified various personal, social, and environmental barriers and enablers. Personal barriers: Private school girls cited body image-related negative consequences of PA participation. Social barriers: Girls from both schools faced more social censure for participating in PA. Environmental barriers: Reduced opportunity for PA in schools was commonly reported across all participants. Personal enablers: All participants reported perceived health benefits of PA. Social enablers: Several participants mentioned active parents and sports role models as motivators for increasing PA. Few environmental enablers were identified. This study highlights the need for further investment in physical activity within schools and for gender-sensitive policies for encouraging PA participation among adolescents in India.