The effects of maternal stress on breastfeeding and ultimately infant health are largely under-studied. This is of particular concern given the documented disparities in rates of breastfeeding initiation and duration among Black women compared to White women in the United States, the underlying causes of which are debated. This study assesses psychosocial stress and levels of peer support among Black and White mothers of infants in Georgia through participant survey, perceived stress scale (PSS), and assay of hair samples for cortisol concentration. Findings suggest maternal cortisol production is tied to parity, perceived stress and perceived social support rather than received social support. Breastfeeding outcomes were associated with increases in maternal age, indicating significant levels of agency and access to resources which support exclusive breastfeeding.