The emergence and rapid spread of COVID-19 led to the development of novel vaccines to fight against the disease. Although COVID-19 vaccines are the major key to controlling the disease and have a good safety profile, they may be associated with some adverse events. Recently, a few studies noted that inadvertent incorrect injection of COVID-19 vaccines may lead to the development of serious adverse events. Herein, we report a case of inadvertent intravenous COVID-19 vaccine injection who developed severe anaphylactic shock following receiving the COVID-19 vaccine. Proper vaccine injection technique training may help to reduce the risk of developing adverse events and improve vaccine safety and efficacy.