The use of corporal punishment (CP) is a strong risk factor for many poor outcomes for children including child maltreatment. The use of CP occurs within social contexts which are important to understand. Although it is known that perceived social norms regarding CP are related to its use, the specific role that a mother's primary support person plays in influencing attitudes toward and use of CP remains unknown. The current study assessed linkages between maternal perceived social support in parenting and perceived injunctive norms of CP from her primary source of support, with maternal attitudes toward and use of CP. Survey data were collected from female primary caregivers (N = 436) of children age 2 to 7 years (mean age = 3.7) enrolled in Special Supplemental Nutrition Program for Women, Infants and Children (WIC) clinics in Southeastern Louisiana. Most frequently, the biological father of the child (37.9%) and the maternal grandmother of the child (24.2%) were identified as the participant's primary source of social support in parenting. Perceived injunctive norms of this support person toward CP use were significantly and positively associated with attitudes toward, AOR = 5.97, 95% CI = [4.04, 8.82], and use of CP, AOR = 3.77, 95% CI = [2.55, 5.59]. However, perceived social support was not associated with these outcomes and also did not moderate these associations. Findings suggest that efforts to reduce maternal risk for child physical abuse and use of CP must include the mother's primary source of social support if they are to be successful.