A pilot survey described the characteristics of anaphylactic events occurring in an initial set of participating U.S. schools during the 2013-2014 school year. This survey was subsequently readministered to large school districts, which were underrepresented in initial results. A cross-sectional survey was administered to the U.S. schools that were participating in the EPIPEN4SCHOOLS® program (Mylan Specialty L.P., Canonsburg, PA) to assess characteristics of anaphylactic events. Data from large school districts were added to initial findings in this comprehensive combined analysis. A total of 1,140 anaphylactic events were reported among 6,574 responding schools. Of 1,063 anaphylactic events with data on who experienced the event, it was observed that it occurred mostly in students (89.5%, 951/1,063). For students, anaphylactic events were reported across all grades, with 44.9% (400/891) occurring in high school students, 18.9% (168/891) in middle school students, and 32.5% (290/891) in elementary school students. Food was identified as the most common trigger (60.1%, 622/1,035). A majority of schools (55.0%, 3,332/6,053) permitted only the school nurse and select staff to administer epinephrine to treat anaphylaxis. The unpredictability of anaphylaxis is emphasized by its high occurrence in individuals with no known allergies (25.0%). A majority of schools permitted only the school nurse and select staff to treat anaphylaxis. Thus, individuals experiencing an anaphylactic event may frequently encounter staff members not being permitted to administer potentially life-saving epinephrine. Epinephrine auto-injectors provided by the EPIPEN4SCHOOLS program were used to treat 38.0% of events. Anaphylaxis can occur in children with no previously known allergies, illustrating the importance of public access to epinephrine.