Background <p>Despite the efficacy of COVID-19 vaccination, the occurrence of side effects has raised concerns among healthcare providers and the general population.</p> Methods <p>The aim of the study was to investigation the administration technique of COVID-19 vaccines and the side effects observed after vaccination. The data for the descriptive and cross-sectional study were collected using the “Patient Information Form”, “Vaccine Administration Checklist Form”, and “COVID-19 Vaccine Side Effects Monitoring Form”. The STROBE checklist was followed to ensure methodological rigour.</p> Results <p>Binary logistic regression analysis conducted in the study identified gender and vaccine type as factors influencing the risk of side effects. Women were found to have a 3.887 times lower likelihood of experiencing side effects (<i>p</i> = 0.005). Also, individuals vaccinated with Turkovac and Sinovac were found to have a lower risk of side effects compared to those vaccinated with BioNTech (<i>p</i> = 0.006 and <i>p</i> = 0.003, respectively).</p> Conclusions <p>The study findings show that the most commonly observed side effects after COVID-19 vaccination are pain at the injection site and tenderness in the extremity. Additionally, gender and vaccine type were found to be significant factors influencing the risk of side effects.</p>