Background: Young mothers (age 14–24 years), who are often low income, are less likely than other mothers to breastfeed for 6 months. They also are more likely to be diagnosed with aggressive forms of breast cancer; breastfeeding significantly reduces this risk. While adolescent breastfeeding has been investigated from the perspective of the individual, the social ecological model recognizes the influence of factors at multiple levels. Research aim: The aim was to identify social and structural barriers to and motivators of breastfeeding that young mothers may encounter. Methods: Using a cross-sectional prospective qualitative design with a community-based participatory research approach, we sought to identify influential factors at each social ecological level: individual, relationship, community, and societal/structural. We used purposeful sampling, and enlisted snowball sampling. We interviewed stakeholder experts (n = 9) and dyads (n = 6) consisting of a young mother and her decision-making partner. Groups of young mothers (n = 6 groups) collectively created community maps while discussing their feelings about infant feeding in different locations. Using collaborative data analysis, we identified themes and categorized barriers and facilitators according to the social ecological levels. Results: Four meta-themes emerged: roles, place, stigma, and support. While some barriers and facilitators were similar to those experienced by mothers of all ages, participants reported multiple overlapping stigmas, requiring more support. Conclusion: Young mothers who decide to breastfeed encounter barriers at multiple levels. Policies and programs aiming to increase breastfeeding rates in this group must address these barriers and enlist identified facilitators.