Secondary prevention of harm from sport-related concussion is contingent on immediate removal from play post-injury. To date, educational efforts to reduce the prevalent risk behavior of continued play while symptomatic have been largely ineffective. Social norms theory may hold promise as a foundation for more effective concussion education aimed at increasing concussion reporting. The primary objective of this study was to assess whether perceived team concussion reporting norms would be less supportive of an individual's safe concussion symptom reporting behavior than objective team norms. Participants were 328 male and female US collegiate athletes. Written surveys were completed in person during the spring of 2014. Among both male and female athletes, team concussion reporting norms were significantly misperceived, with athletes tending to think that they themselves have safer attitudes about concussion reporting than their teammates. Perceived norms were associated with symptom reporting intention, independent of the team's objective reporting norm. A social norms approach to concussion education, in which misperceived group norms are corrected and shifted in the direction of safety, is an important avenue for program development and evaluation research aimed at the secondary prevention of harm from concussion. Implications for the design of this type of educational programming are discussed.