Iranian Journal of Nursing and Midwifery Research1735-906631320260729408412ENDepartment of Nursing, Institut Ilmu Kesehatan Nahdlatul Ulama, Tuban, East Java, IndonesiaDepartment of Nursing, Institut Ilmu Kesehatan Nahdlatul Ulama, Tuban, East Java, IndonesiaAirlangga University, Surabaya, East Java, IndonesiaAirlangga University, Surabaya, East Java, Indonesia,Airlangga University, Surabaya, East Java, Indonesia,Department of Nursing, Universitas Muhammadiyah East Kalimantan, Samarinda, East Kalimantan, Indonesia2026072720260727<p><strong>Background: </strong>The problem faced during the puerperium period is the inability of some women to engage in breastfeeding. Several factors, including self‑efficacy, influence the breastfeeding rate. This study aims to determine the relationship between self‑efficacy and the level of knowledge, social support, and attitudes toward breastfeeding in early postpartum women. <strong>Materials and Methods: </strong>A cross‑sectional design was used with postpartum primipara as the population from day 14 to 42 days. A total of 180 respondents were selected as samples, and the variables measured were breastfeeding self‑efficacy, level of knowledge about breastfeeding, social support for breastfeeding, and attitudes toward breastfeeding. A total of 180 respondents were selected using purposive sampling, and the variables measured were breastfeeding self‑efficacy, level of knowledge, social support, and attitudes toward breastfeeding using a questionnaire. Additionally, the data obtained were examined utilizing Multivariate Linear Regression Analysis. <strong>Results: </strong>The results indicated that breastfeeding women’s knowledge, social support, and attitudes accounted for 26.36% of the variation in the score of breastfeeding self‑efficacy. Breastfeeding self‑efficacy scores, as well as knowledge (<em>t </em>= 4.24, <em>p </em>&lt; 0.001), social support (<em>t </em>= 2.56, <em>p </em>= 0.011), and attitudes toward breastfeeding (<em>t </em>= 4.44, <em>p </em>&lt; 0.001), were found to have significant relationships. <strong>Conclusions: </strong>Positive breastfeeding self‑efficacy in breastfeeding can influence knowledge, social support, and improved attitudes.</p><p> </p>http://ijnmr.mui.ac.ir/index.php/ijnmr/article/view/2387http://ijnmr.mui.ac.ir/index.php/ijnmr/article/download/2387/70707975