Background and objective: This study was conducted to investigate the psychological and emotional effects of gardening activities held on the campus of D University on parents of children with developmental disabilities.Methods: There were 12 study subjects, including 11 parents of children with developmental disabilities, and 1 grandmother as a primary caregiver. A gardening program was conducted for 30 sessions twice a week over 3 months, from August 21 to November 27, 2021. Gardening activities including gardening practice and plant monitoring were performed in a 'healing garden' on the campus of D University, in a program designed to combine activities on the trail and those in an outdoor garden on the campus. Tests were conducted to verify the effects of such activities, including the Parenting Stress Index (K-PSI-4) and Korean-style mental health assessment (MHA) with 5 types of scales (depression, anxiety, daily vitality, quality of life, and mindfulness).Results: Based on the K-PSI-4 results, the total parenting stress level was decreased from 261.6 points in the pre-test to 241.5 points in the post-test, and notably, the stress level in the Child domain decreased by a significant level, from 120.1 to 109.1 points (<i>p</i> < .05). In the subscale of Acceptability in the Child domain, and the subscale of Isolation in the Parent domain, there were significant changes, from 19.6 to 17.2 points and from 16.2 to 12.6 points, respectively (<i>p</i> < .05). Based on the Korean-style MHA results, there were significant changes in depression, from 3.34 points in the pre-test to 1.24 points in the post-test, and in the daily vitality scale, from 18.25 to 21.38 points (<i>p</i> < .05). In a survey of participants' satisfaction with the program, all participants answered that their daily stress was relieved, which was the most common response given. This was followed by "acquiring knowledge about plants and gardens" and "maintaining physical health."Conclusion: The gardening program had psychological and psychological effects on parents of children with developmental disabilities, including the effects of reducing parenting stress and lowering depression and anxiety. It is expected that gardening programs will play a good role as a support program for persons with disabilities or diseases, as well as for their caregivers and guardians.