BACKGROUND: Lung cancer is the malignant tumor with the highest morbidity and mortality rate in China. Although chemotherapy is effective in improving clinical symptoms, it causes a variety of acute and chronic side effects, seriously aggravating the psychological stress of patients. Laughter Yoga as a new type of aerobic exercise can effectively reduce stress levels and increase positive mood in patients. This study aimed to examine the effects of laughter yoga on perceived stress, positive psychological capital, and exercise capacity in lung cancer patients. METHODS: This study was a randomized, single-blind, parallel-group trial. The study enrolled 84 lung cancer chemotherapy patients from a general hospital in central China. These patients were randomly allocated to control and intervention groups (n = 42 per group) after baseline assessments. Patients in the control group received routine care and those in the intervention group received laughter yoga intervention. Perceived stress, positive psychological capital, and exercise capacity were assessed at baseline, immediately post-intervention. RESULTS: During the implementation of the study, there were 2 dropouts in each of the intervention and control groups. Ultimately, 80 patients in the control and intervention groups completed the trial. Patients who received laughter yoga intervention had significantly higher scores in positive psychological capital (P < .01, Cohen's d = 0.692) and exercise capacity (P < .01, Cohen's d = 0.659). Discernible differences were also observed in perceived stress (P < .01, Cohen's d = 1.087) between the 2 groups. CONCLUSIONS: The results of this study suggest that laughter yoga is an effective way and may produce beneficial effects on perceived stress, positive psychological capital and exercise capacity.