Psycho-social factors are key factors to the powerlessness of infant mothers who breastfeed. As the theory of planned behavior (TPB) is widely used to investigate the correlation between psycho-social factors and breastfeeding behavior, this study aims to examine the utility of TPB constructs to predict breastfeeding behavior and understand TPB-based psycho-social factors’ effectiveness on breastfeeding behavior. A narrative review consulting Web of Science, Scopus, Ebsco, PubMed, and PsycInfo in English and Chinese has been conducted, with the inclusion of twenty studies published between January 2000 and May 2022. It is reported that psycho-social factors based on TPB for breastfeeding such as affective attitude, instrumental attitude, subjective norm, perceived behavioral control (including self-efficacy), moral norm, breastfeeding knowledge, and self-identity can effectively explain the breastfeeding behavior. Future research should improve the theoretical model of TPB-based breastfeeding and implement more localized prediction and intervention studies on breastfeeding.