COVID-19 infection usually causes mild symptoms in children. Mortality and morbidity of the disease have decreased with the widespread use of vaccines. COVID-19 vaccines are generally known to protect against the disease and its complications. In this case report, a thirteen-year-old patient who came to the pediatric emergency department with chest pain, received two doses of BNT162b2 (Pfizer-Biontech), and was diagnosed with acute COVID-19-associated myocarditis is presented. With this case, it was emphasized that it may be necessary to make vaccination reminder doses at shorter intervals in order to evaluate those with chronic diseases separately from healthy children and to maintain effective protection against COVID-19.