Human milk sharing (HMS) is a poorly understood, emergent infant-feeding practice involving the commerce-free exchange of expressed human milk (HM). In this dissertation, we took an exploratory mixed-methods approach to investigate HMS experiences, practices, and risk perspectives among milk-sharing parents. Ethnographic interviews were conducted with 30 HMS recipients in Washington, DC. Interviews were recorded, transcribed, and iteratively analyzed using an inductive approach to identify and analyze emergent themes. These data were used to inform the development of a quantitative online survey of milk-sharing practices that was distributed to 168 HMS participants (98 recipients, 70 donors) in Washington, DC. Descriptive analyses were used to summarize the data by donor/recipient status. Latent profile analysis (LPA) was used to identify discrete risk perspectives among donors and recipients. Our survey results demonstrated that HMS participants achieved a high duration of lactation and HM-feeding and recipients engaged in a wide variety of risk-mitigation practices. While sociodemographically similar, donors and recipients differed substantially in their maternal experiences and infant-feeding practices. The LPA detected heterogeneity in risk perspectives among HMS participants, which underscored the complexity of infant feeding risk constructions. The LPA results confirmed that HMS risk is interpreted relative to infant-formula risk. Beliefs about infant formula and the importance of donor familiarity emerged as important constructs in parents’ risk perspectives. Our qualitative study demonstrated that the experience of HMS recipients is often a product of infant-feeding challenges that evoke feelings of guilt and shame. Emergent themes about recipient decision-making revealed careful and thoughtful analysis of infant-feeding options. Trust of breastfeeding mothers, a high value placed on human milk, and mistrust of infant formula played key roles in the decision to milk share. These findings highlight important features of the milk-sharing experience and emphasize the need for evidence-based, non-judgmental support for families who experience breastfeeding challenges or seek alternative infant-feeding options. Better understanding of the risk perspectives held by HMS participants is critical for elucidating parental decision-making processes and developing more targeted approaches to patient care and messaging about infant feeding.