This study was designed as a randomized controlled trial to identify the effects of laughter yoga on the psychological well-being of women diagnosed with gynecologic cancer. The study was conducted with 70 patients (35 patients in the intervention group and 35 patients in the control group) receiving treatment at the oncology service of a research and training hospital in western Turkey from 1 October 2021 to 1 April 2022. The data were collected with a Demographic Information Form and the Psychological Well-Being Scale. It was found that the intervention and control groups had similar mean pretest Psychological Well-Being Scale scores, wheres the mean posttest score of the control group was significantly lower than its mean pretest score (p<0.05), and the mean posttest score of the intervention group was significantly higher than its mean pretest score (p<0.05). In light of the results of the study, it is recommended that laughter yoga be generally integrated into nursing care and practiced to enhance the psychological well-being of oncology patients. It is also recommended that settings be created for nurses with laughter yoga certification at oncology outpatient clinics in hospitals and early diagnosis, screening, and training centers providing care to cancer patients.