Purpose: The purpose of this study was to explore the nurses’ experience of the side effects of COVID-19 vaccination and understand its meaning. Methods: This study was a qualitative study using the content analysis method. The data collection period using a focus group was from October 26, 2021 to January 23, 2022. Results: The themes included: “Pressure from mandatory COVID-19 vaccination”, “Feeling relieved because the side effects are mild”, “Severe vaccine side effects cause negative emotions”, “Tolerating side effects and coping personally”, “Confusion and alienation about insufficient coping of side effects”, “Feeling skeptical about the COVID-19 vaccination policy”, “Thinking about how to build trust in the COVID-19 vaccine”. Conclusion: In the future, it is considered important to establish scientific evidence through continuous monitoring and data collection of the side effects of COVID-19 vaccination and to build trust in vaccines through transparent information disclosure.