Purpose: This paper describes a model of "Learning to care" derived from a study exploring how care workers in care homes learn to care for people living with dementia. The "Learning to care" model is primarily informal in nature in which influences such as formalised training and organisational culture impact care outcomes indirectly rather than directly. Design/methodology/approach: This study used a focused, critical ethnographic approach in two care homes in England resulting in 63 h of observation of care of people living with advanced dementia, 15 semi-structured interviews and 90 in-situ ethnographic interviews with care staff. Findings: The findings reveal a three-level model of learning to care. At the level of day-to-day interactions is a mechanism for learning that is wholly informal and follows the maxim "What Works is What Matters". Workers draw on resources and information within this process derived from their personal experiences, resident influences and care home cultural knowledge. Cultural knowledge is created through a worker's interactions with colleagues and the training they receive, meaning that these organisational level influences affect care practice only indirectly via the "What Works is What Matters" mechanism. Originality/value: This study makes an original contribution by explaining the nature of day-to-day informal learning processes as experienced by care workers and those living with dementia in care homes. In particular, it illuminates the specific mechanisms by which organisational culture has an effect on care practice and the limitations of formal training in influencing such practice.