Background: Despite increased awareness of concussions, epidemiologic surveillance efforts have been scarce, especially among adolescents. This project, which was developed with school stakeholders (certified athletic trainers [ATCs], nurses, athletic directors), piloted a public secondary school-based online surveillance tool for interscholastic and intramural sports and physical education-related concussions in New Jersey during 2014-2017 school years (SY). Methods: Participating public high schools (5 within 4 districts) and career-technical-vocational education districts (2 with 5 campuses) completed forms anonymously online via PsychData within 5 days. Results: There were 208 concussions reported, 115 in 2015-2016 SY and 93 in 2016-2017 SY. In fall 2015, 86 concussions were reported, including 16 from summer preseason. In fall 2016, 56 concussions were reported; 3 occurred during preseason. There were 7 concussions reported in winter 2016 and 16 in winter 2017. Twenty-two concussions were reported in spring of both 2016 and 2017. Most online forms were completed in <10 minutes, usually using either desktop computers or tablets/iPads. School nurses followed by ATCs were primary sources of data entered online, usually by ATCs. Conclusions: Cooperation of nurses and ATCs at participating schools suggested online surveillance was valued and viable. Data inform future concussion prevention education and ongoing injury surveillance.