Limited data are available regarding severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence in children. In this study, we assessed for the first time the seroprevalence of SARS-CoV-2 in children from Romania. Serum samples of 379 children were investigated for the presence of SARS-CoV-2 total antibodies. Serologic tests were performed using Elecsys Anti-SARS-CoV-2 electrochemiluminiscence immunoassay that targets the nucleocapsid protein of the virus. The overall seroprevalence of SARS-CoV-2 total antibodies was 46.70%. No significant difference was observed between seropositive and seronegative children according to age groups, gender, and area of residence. Our findings revealed a high SARS-CoV-2 seroprevalence in Romanian children at the end of the third COVID-19 pandemic wave. Results suggest that children, regardless of age, gender, or area of residence, are susceptible to infection with SARS-CoV-2. Seroprevalence in children was similar to the seroprevalence reported in the adult population from Western Romania during the same period of time, March to June 2021.