OBJECTIVES: (a) to apply an organisation-level, pre-implementation theory to identify and describe factors that may impact hospitals' readiness to achieve the Ten Steps and (b) to explore whether/how these factors vary across hospitals. DESIGN: a multisite, descriptive, qualitative study of eight hospitals that used semi-structured interviews of health-care professionals. Template analyses identified factors that related to organisation-level theory. Cross-site comparative analyses explored how factors varied across hospitals. SETTING: thirty-four health-care professionals from eight North Carolina hospitals serving low-wealth populations. The hospitals are participating in a quality improvement project to support the implementation of the Ten Steps. This study occurred during the pre-implementation phase. FINDINGS: several factors emerged relating to collective efficacy (i.e., the shared belief that the group, as a whole, is able to implement the Steps) and collective commitment (i.e., the shared belief that the group, as a whole, is committed to implementing the Steps) to implement the Ten Steps. Factors relating to both constructs included 'staff age/experience,' 'perceptions of forcing versus supporting mothers,' 'perceptions of mothers' culture,' and 'reliance on lactation consultants.' Factors relating to commitment included 'night versus day shift,' 'management support,' 'change champions,' 'observing mothers utilize breastfeeding support.' Factors relating to efficacy included 'staffing,' 'trainings,' and 'visitors in room.' Commitment-factors were more salient than efficacy-factors among the three large hospitals. Efficacy-factors were more salient than commitment-factors among the smaller hospitals. KEY CONCLUSIONS AND IMPLICATIONS FOR PRACTICE: interventions focused on implementing the Ten Step may benefit from improving collective efficacy and collective commitment. Potential approaches could include skills-based, hands-on training highlighting benefits for mothers, staff, and the hospital, and addressing context-specific misconceptions about the Steps.