The objective was to describe infant feeding practices, nutrition and related health aspects of infants under six months among Syrian refugees in Greater Beirut, Lebanon. A cross-sectional study was conducted among Syrian refugee mothers with infants under six months in July–October 2018 (N = 114). Additionally, eleven focus group discussions were conducted to explore supportive factors and barriers associated with early breastfeeding practices. The prevalence of pre-lacteal feeding was high (62.5%), whereas early initiation of breastfeeding was low (31%), and exclusive breastfeeding very low (24.6%). One-fifth of the infants were anemic (20.5%) and 9.6% were wasted. A significantly higher proportion of non-exclusively breastfed infants had a fever and took medicines than those who were exclusively breastfed. Supporting factors of adequate infant feeding practices comprised knowledge on maternal nutrition and exclusive breastfeeding, along with receiving support from healthcare professionals and family members. Identified barriers included preterm delivery, pre-lacteal feeding, an at-risk waist circumference and moderate to severe depression among mothers, bottle feeding, early introduction of food, maternal health reasons, breastmilk substitutes’ distribution, and misinformation offered by mothers-in-law. To address sub-optimal feeding practices documented among Syrian refugees, awareness on proper breastfeeding practices, maternal nutrition, and psychosocial support should be provided to mothers and family members alike.