Introduction: Breastfeeding myths are culturally ingrained misconceptions related to breastfeeding and adversely affect the breastfeeding process. The objective of this study is to develop the Breastfeeding Myths Scale. Methods: This methodological study was conducted with a total of 413 participants. In the first phase, exploratory factor analysis was employed, followed by confirmatory factor analysis in the second phase. Furthermore, a test–retest was conducted to assess the reliability of the scale scores. Results: As a result of psychometric analyses, the single-dimensional 30-item Breastfeeding Myths Scale was deemed a valid and reliable instrument. The Cronbach's alpha value of the scale was established at 0.91, and the test–retest reliability at 0.90. According to the results of the receiver operating characteristic analysis, the optimal cutoff point was determined to be 119.50, with a sensitivity of 86% and a specificity of 53%. Conclusions: Breastfeeding Myths Scale was deemed significant for identifying the prevalence of breastfeeding myths. Utilization of the Breastfeeding Myths Scale is recommended for future research endeavors and individual clinical assessments.