Human breastmilk is the optimal nutrition for infants; however, preliminary research suggests that women who experience intimate partner violence (IPV) are less likely to initiate and continue breastfeeding. Self-efficacy is a known facilitator to achieve positive breastfeeding outcomes. This study aimed to explore the relationship between experiencing IPV and breastfeeding duration, exclusivity, and self-efficacy for Canadian mothers, and to identify potential variables that influence breastfeeding decision-making among women with experiences of IPV. This was a cross-sectional secondary analysis of surveys completed by 129 mothers with children under the age of 2 years from Ontario, Canada. Data were stratified according to those who had experienced IPV and those who had not. Breastfeeding outcomes assessed included breastfeeding self-efficacy and breastfeeding duration and exclusivity. Non-parametric tests and correlations were used to determine if relationships existed between IPV and breastfeeding outcomes. 72.3% (n = 94) of women in this sample breastfed their child(ren). Experiencing IPV was associated with lower breastfeeding self-efficacy scores (W = 768, p = 0.055) with a moderate effect size (r = 0.32 [95% 0.06,0.55]). This relationship was significant in the context of psychological abuse (W = 816.5, p = 0.015) with a small effect size (r = 0.22 [95% 0.03,0.41]). This study provides novel preliminary evidence suggesting that experiencing IPV of any type can negatively impact breastfeeding self-efficacy, with psychological abuse potentially being the most detrimental. Future research is required to build upon these findings.