This systematic review will summarize the evidence on how participation in WIC is associated with outcomes for women and children. This review will be inclusive in its consideration of study designs utilized to evaluate WIC participation and maternal and child outcomes, but also evaluate the quality of evidence provided by studies, and consider how studies have characterized participation of women and/or children in WIC, to best inform what is known and what are the evidence gaps to be addressed in future research. Because the questions for the review seek evidence among sub-groups of WIC participants, the review will indirectly address whether WIC participation addresses inequities in outcomes for women and children.