Edible flowers are a rich source of nutritional, phytochemical, and antioxidant compounds, leading to their increasing popularity among consumers. The pansy plant, as an edible flower, possesses medicinal properties and is widely used in various foods and beverages. Research indicates that melatonin application can have beneficial effects on improving plant quality. This study aimed to investigate the effect of melatonin on the nutritional characteristics of pansy in a completely randomized design with three replications in a greenhouse. Treatments included melatonin at concentrations of 0, 50, 100, 150 and 200 mg l-1, applied in two stages. The first application was two weeks after transplanting, and the second occurred ten days later. One week after the last spraying, the flowers were harvested to evaluate the desired traits. The results showed that the highest cell membrane stability index (87.56%), carotenoid (5.58 mg g-1), total chlorophyll content (5.38 mg g-1), total antioxidant activity (6.53%), vitamin C (49.25 mg 100g-1), thiamine (3.17 µg g-1), riboflavin (0.134 µg g-1), niacin (131.24 µg g-1), and phenol content (19.85 mg g-1) were observed in melatonin 150 mg l-1 treatment. The highest folic acid content (0.53 µg g-1), carbohydrate (82.35 mg g-1), and protein content (14.76 µg g-1) were obtained in melatonin 200 mg l-1 treatment. According to the finding, applying 150 mg l-1 melatonin significantly improved the nutritional quality of Viola × wittrockiana flowers.