Background <p>Belongingness is considered an important factor contributing to a clinical learning environment for good learning outcomes and higher levels of satisfaction among nursing students. This study investigated the mediating influence of a sense of belonging on the relationship between the clinical learning environment and perceived stress.</p> Methods <p>This cross-sectional study was conducted using a convenience sample of 455 internship nursing students from August to November 2023. Data were collected using the Belongingness Scale-Clinical Placement Experience, Perceived Stress Scale, Clinical Learning Environment Scale, and Supervision Scale.</p> Results <p>The mean of nursing internship students’ belongingness was 121.27 ± 14.95. The majority of participants had moderate stress levels (83.3%). The direct effects analysis revealed a significant negative correlation between the clinical learning environment, supervision, and perceived stress (β = − 0.484, <i>p</i> &lt; .001). Clinical learning environment and supervision had a positive direct effect on belongingness (β = 0.499, <i>p</i> &lt; .001). Belongingness had a negative effect on perceived stress (β = − 0.163, <i>p</i> = .003). According to further indirect effect analysis (β = − 0.081, <i>p</i> = .003), the association between the clinical learning environment and supervision-perceived stress was mediated by belongingness. Overall, the results showed that felt stress was considerably affected by the clinical learning setting and supervision (β = − 0.565, <i>p</i> &lt; .001).</p> Conclusion <p>A sense of belonging is a critical factor for alleviating the impact of an overwhelming environment. These findings emphasize the need to provide a positive environment that promotes the health of internship nursing students.</p> Clinical trial number <p>Not applicable.</p>