Objective: To identify barriers and facilitators to adherence to safe sleep practices (SSP) among mothers of preterm infants using qualitative methodology. Design: We conducted 23 in-depth interviews in English or Spanish with mothers of preterm infants who were recently discharged from four hospitals, utilizing a grounded-theory approach and framework of the Theory of Planned Behavior (attitudes, perceived control, social norms). Results: For attitudes, mothers’ fear about their infants’ vulnerable preterm state related to suffocation, apnea of prematurity, and reflux influenced infant sleep practices. For social norms, education received in the NICU and advice from other health care providers, family, friends, and media impacted their choices. For perceived control, mothers adapted infant sleep practices to meet their own needs and address the perceived safety and comfort of infants. Conclusion: Factors identified that influence maternal decision-making about infant sleep practices can inform interventions to address sudden unexpected infant death reduction in preterm infants.