United States breastfeeding rates fall short of Healthy People 2030 goals. Mother-baby dyads encounter barriers to breastfeeding, resulting in early weaning. Military families experience additional difficulties, including frequent relocations. Breastfeeding rates increase with lactation support from trained nurses with adequate knowledge. Existing research on breastfeeding knowledge focuses on inpatient settings, with little research on outpatient nurses or the military health system. This study evaluates breastfeeding knowledge, attitudes, and intentions of outpatient military health system nurses. Nurses were recruited primarily through social media. Participants completed the Comprehensive Breastfeeding Knowledge Scale and the Nurses’ Support for Breastfeeding Questionnaire attitude and intention subscales. Nonparametric statistical analysis was conducted due to violated assumptions of normalcy. Knowledge, attitude, and intention scores were high, with medians of 77 (9), 19 (7.5), and 16 (6), respectively. Nurses’ knowledge scores were only higher than mothers’ scores at four weeks postpartum, t(46) = 2.3, p = 0.26. Attitude and intention were positively correlated, τ_b = .43, p = .042. Registered nurses demonstrated higher knowledge than licensed practical nurses, z = -2.14, p = .032, r = -.57. Nurses reporting neutral personal breastfeeding experience had lower knowledge scores than nurses reporting positive personal breastfeeding experience, z = -2.26, p = .024, r = -.80, or no personal breastfeeding experience, z = -1.994, p .046, r = - .66. Outpatient military health system nurses demonstrate knowledge, attitudes, and intentions consistent with an ability to support the breastfeeding dyad at four weeks postpartum but may not provide effective lactation support at other time points. Stakeholders should be aware that nurses’ personal breastfeeding experience may affect ability to provide high-quality support.