Background: Coaches, athletic trainers (ATCs), and parents/guardians (parents) are important contributors to the proper identification and management of concussions in student-athletes. However, there are limited studies on the identification of concussion knowledge gaps that will help inform educational efforts and improve concussion outcomes in these groups.Objective: To identify gaps and factors influencing concussion knowledge for high school athletics.Design: Survey.Setting: Public, private, and recreational leagues in New Jersey.Participants: 41 coaches, 34 ATCs, and 65 parents of high school student-athletes.Methods: A 17-item online survey examining concussion knowledge was distributed to coaches, ATCs, and parents. Analyses included ANOVA for between-group comparisons of continuous variables and Pearson's correlations for categorical data.Main Outcome Measurements: Demographics, concussion knowledge, application of knowledge, access to educational materials, and confidence in the ability to identify concussions.Results: Significant between-group differences were found for overall knowledge (F[2137] = 11.0, P < .001), factual knowledge (F[2137] = 8.7, P < .001), and application of knowledge (F[2137] = 3.5, P = .03), with parents scoring lower. Coaches, ATCs, and parents had gaps in factual knowledge of baseline testing scores and identification regarding symptom severity. More coaches (73.2%) and ATCs (97.1%) felt confident in concussion knowledge compared with parents (31.3%; P < .001). All groups thought mandatory education, new law, and guidelines were positive in promoting better care of student-athletes.Conclusions: Knowledge gaps were identified in all groups. Educational programs for these groups should consider including targeted techniques, including vignettes, to illustrate application of concussion knowledge.Level Of Evidence: III. [ABSTRACT FROM AUTHOR]