Nutrition during the first 1000 days of life is critical for lifelong physical and mental health. Infant milk choices, introduction of complementary foods, and responsive feeding methods can contribute to risk for infection, chronic disease, mental health, and later nutrition and dietary practices. Current feeding interventions are likely to focus on the mother’s decision-making and frequently neglect to explore the impact of the people around her. Little is known about how social networks can influence feeding decisions and how this may impact the acceptance of recommendations from health professionals or intervention content. This dissertation used a convergent mixed methods approach to explore how social networks influence infant feeding decisions and practices for Latinx women in the U.S. In the quantitative portion, 30 participants completed egocentric network mapping to explore network structure and tie strength. In the qualitative portion, 15 of the participants completed in-depth interviews to allow for a better understanding of the influence that network members have, as well as mothers’ decision-making processes. The quantitative and qualitative strands were integrated to allow for a deeper understanding of the social context in which feeding decisions are made. Three manuscripts are presented in the dissertation. The first explores infant feeding support networks and other social influences, including culture and maternal intuition. The participants tended to have small networks and different levels of cultural influence depending on immigration status. The second manuscript examined the influence of information about infant feeding from personal communication compared to online channels. Participants valued the information from medical providers or their support networks and although many used the internet, they had concerns about the information found there. The third manuscript looked at the experiences of the participants who were formula-feeding during the 2022 formula shortage. Although the participants fought to breastfeed their children, they needed to switch to formula to protect their physical and mental health and be there for them. The formula shortage added stress and took an emotional toll on the participants. The dissertation results confirm the importance of social networks as sources of information and support for Latinx mothers with infants during the first year of life. Overall, there was a need for additional support during this time and additional barriers to infant feeding for immigrant mothers. Direct practice implications include how interventions can be developed to provide support. Policy implications include the need to improve structural support for infant feeding, including access to lactation care and food. Future research should continue to assess network support and could look at sociodemographic differences.