Background <p>Given the fundamental role of compassionate care in nursing, it is essential to integrate strategies that enhance self-compassion and compassion for others into nursing education. This study aimed to investigate the effect of inquiry-based stress reduction on self-compassion and compassion for others among undergraduate nursing students.</p> Methods <p>This quasi-experimental study employed a pretest-posttest control group design. Seventy third-year nursing students were selected using a convenience sampling method and then randomly assigned to either an intervention group (<i>n</i> = 35) or a control group (<i>n</i> = 35). The intervention group participated in an inquiry-based stress reduction program consisting of two-hour sessions held twice weekly for three weeks, while the control group received no intervention. All participants completed the Sussex-Oxford Compassion for Others Scale and the Self-Compassion Scale before and one month after the intervention.</p> Results <p>The results revealed a statistically significant increase in self-compassion score of the intervention group after the intervention (87.68 ± 10.84) compared to before the intervention (75.4 ± 11.91) (<i>P</i> &lt; 0.001, Cohen’s d = 1.07, with a very large effect). However, the control group showed no significant change in self-compassion scores before and after the intervention (74.74 ± 11.39 vs. 75.88 ± 11.32) (<i>P</i> = 0.12). Similarly, the intervention group experienced a significant increase in compassion for others score after the intervention (57.3 ± 6.9) compared to before the intervention (42.6 ± 5.3) (<i>P</i> &lt; 0.001, Cohen’s d = 2.38, with a very large effect). However, the control group showed no significant change in compassion for others scores before and after the intervention (42.2 ± 5.3 vs. 43.4 ± 5.2) (<i>P</i> = 0.06).</p> Conclusions <p>The inquiry-based stress reduction program enhanced self-compassion and compassion for others among nursing students. This intervention is recommended for medical students, particularly nursing students, who often work in demanding hospital environments with direct patient interaction, to mitigate stress in clinical settings.</p> Clinical trial number <p>Not applicable.</p>