Background <p>Emotional Freedom Technique (EFT) is a complementary method used to reduce psychological distress and enhance self-efficacy. Postpartum women with maternity blues often experience emotional difficulties that may negatively affect breastfeeding. Evaluating the effect of EFT on maternity blues and breastfeeding self-efficacy can contribute to improving postpartum care.</p> Methods <p>This randomized controlled, parallel-group study with a pre-test–post-test design included 64 breastfeeding women aged 18–39 who had a Maternity Blues Scale score above 100. Data were collected using the Personal Information Form, Maternity Blues Scale, and Breastfeeding Self-Efficacy Scale–Short Form. The intervention group received two sessions of EFT, each lasting approximately 45–60&#xa0;min, while the control group received routine breastfeeding counseling.</p> Results <p>In this study, we investigated the effect of EFT on breastfeeding outcomes in women experiencing maternity blues. Following the intervention, EFT significantly reduced maternity blues scores (post-test Z = -6.880, <i>p</i> &lt; 0.001) and increased breastfeeding self-efficacy scores (post-test Z = -6.380, <i>p</i> &lt; 0.001). Specifically, the mean Maternity Blues Scale (MBS) score decreased by 57.5%, corresponding to a large effect size (Cohen’s d = -3.72), while the mean Breastfeeding Self-Efficacy Scale–Short Form (BSES-SF) score increased by 33.7%, also demonstrating a large effect size (Cohen’s d = 2.55). These findings indicate that EFT had a substantial positive impact on reducing postpartum emotional distress and enhancing breastfeeding confidence among mothers.</p> Conclusion <p>EFT stands out with its easy applicability, effectiveness, low cost, and non-invasive structure. This study demonstrates that EFT can effectively alleviate maternity blues and enhance breastfeeding self-efficacy, highlighting its potential as a practical intervention for postpartum care.</p> Trial Registration <p>Clinicaltrials.gov NCT06129292.</p>