Focus group discussions with young first-time mothers (FTMs), male partners, mothers, and mothers-in-law to identify norms that influence exclusive breastfeeding found important barriers. For instance, FTMs believed exclusive breastfeeding was uncommon and would result in social sanctions from the community. Trust in and desire to please mothers, friends, and others in their social networks also influenced decision-making. The authors conclude that to promote exclusive breastfeeding it is critical to assess cultural beliefs, target sensitization efforts to key influencers, and increase FTMs’ self-efficacy.