Background: Auricular acupressure influences pain reduction in patients with diseases. However, study results on its influence on breast pain, common among breastfeeding mothers, are insufficient. Research Aim: This study aimed to explore the effectiveness of auricular acupressure on breast pain among breastfeeding mothers who also received a standard gentle hand technique. Methods: This was a placebo-controlled study wherein auricular acupressure was provided for 4 weeks to 52 breastfeeding mothers consulting a local breastfeeding clinic. In the intervention group, auricular acupressure was applied to specific acupoints, including Shenmen, central rim, breast, and endocrine, which are related to breast pain and postpartum lactation. For the placebo control group, auricular acupressure was applied to acupoints not related to breast pain. The degree of breast pain was assessed using a numeric rating scale and a pressure algometer. Results: After 4 weeks of auricular acupressure, numeric rating scale pain scores did not show a significant change. However, the pressure pain threshold for the upper left (Z = −2.202, p = .028) and upper right (t = 2.613, p = .012) areas of the right breast increased significantly in the intervention group. Conclusion: This study employed subjective and objective measurements to evaluate the efficacy of auricular acupressure in alleviating breast pain. The intervention shows potential as a nursing measure. Further research is required to determine the optimal intervention duration and frequency, particularly for breastfeeding parents with severe pain, and to evaluate long-term outcomes.