Breast milk (ASI) is the primary source of nutrition for newborns and plays a crucial role in growth, development, and immune system formation. However, many postpartum mothers experience suboptimal milk production, which may hinder the success of exclusive breastfeeding. Non-pharmacological efforts, including the use of herbal remedies, are often applied to support lactation. One of the plants believed to have galactagogue effects is papaya leaves (Carica papaya L.), which contain bioactive compounds such as papain, flavonoids, vitamins A, C, and E, as well as minerals that stimulate prolactin and oxytocin hormones, thereby enhancing milk production. This study aimed to determine the effect of consuming papaya leaf decoction on breast milk production among postpartum mothers. The research design employed a pre-experimental method with a pretest–posttest approach. A total of 30 postpartum mothers were selected based on inclusion criteria. Breast milk production was measured before and after the intervention of papaya leaf decoction, and the data were analyzed using the Paired Sample T-Test with SPSS version 27. The results showed that the mean breast milk production before intervention was 67.03 ml, ranging from 60 to 80 ml. After consuming papaya leaf decoction, the mean increased to 130.63 ml, with a range of 70–180 ml. Statistical analysis revealed a p-value of 0.000 (p < 0.05), indicating a significant difference in breast milk production before and after the intervention. In conclusion, papaya leaf decoction significantly increases breast milk production in postpartum mothers. This finding recommends papaya leaf decoction as a simple, natural, and affordable herbal intervention to support the success of exclusive breastfeeding programs.