Abstract Introduction Health and social care organizations continually face change to coordinate efforts, improve care quality and better meet patient needs in the context of growing pressure on services. NHS ‘vanguard’ teams funded to pilot organizational change in England have argued that alongside new structures, policies and governance, a shift in ‘workplace culture’ is needed to implement change. Although now defined in the literature and seen as an important driver of quality care, it was not clear what teams themselves meant when discussing workplace culture. Methods In a qualitative study nested in a wider behavioural science programme, 34 managers and frontline NHS staff took part in interviews and focus groups on the role and meaning of ‘workplace culture’ in their experience of change. Participants were from organizations in four NHS England vanguards implementing new models of care. Inductive thematic analysis revealed six interlinking themes: unity, emotions, support, consistency, openness to innovation and performance. Results The term ‘workplace culture’ was nuanced and used in various ways. It was seen as a determinant, measure and/or consequence of change and linked to workplace behaviours, emotions and cognitions. Participants agreed that imposed top-down change in new models of care was a common cause of damaged culture and had knock-on effects on care quality, despite manager accounts of the importance of staff ideas. Discussion Our findings suggest that exploring teams’ own meanings of culture and behaviour change barriers, gathering ideas and co-developing tailored support would help overcome cultural challenges in implementing new models of care.