BackgroundCare home staff are key providers of palliative and end-of-life care. Yet, little is known about how care home characteristics can influence care leader’s confidence in their ability to provide optimal palliative and end-of-life care.AimTo understand the influence of care home registration type (nursing, residential or dual registered) and size on senior care leader’s confidence to provide palliative and end-of-life care.DesignAn explanatory sequential mixed methods study comprising an online cross-sectional survey (including the Palliative Care Self-Efficacy Scale) and qualitative individual interviews. Analysis of survey data used a multivariate logistic regression and qualitative interview data used Framework Analysis. A ‘Following the Thread’ method was undertaken for data integration.Setting/participantsUK care home senior care leaders, purposively sampled by registration type, size and geographical location.ResultsThe online survey (N = 107) results indicated that nursing home senior care leaders had higher confidence scores on the Palliative Care Self-Efficacy Scale than residential care home leaders (aOR: 3.85, 95% CI 1.20-12.31, p = 0.02). Care home size did not show effect when adjusting for registration type (medium - aOR 1.71, 95% CI 0.59–4.97, p = 0.33; large – aOR 0.65, 95% CI 0.18–2.30, p = 0.5). Interviews (n = 27) identified three themes that promote confidence, (1) ‘feelings of preparedness’ stemming from staff expertise and experience and care home infrastructure, (2) ‘partnership working’ with external services as a valued member of the multidisciplinary team, and (3) a shared language developed from end-of-life care guidance.ConclusionCare home senior care leader’s confidence is influenced by care home characteristics, particularly availability of on-site registered nurses and the infrastructure of large care homes. All care home leaders benefit from training, working with external, multidisciplinary teams and use of guidance. However, mechanisms to achieve this differed by care home type and size. Further exploration is needed on successful integration of palliative care services and interventions to enhance confidence in residential care homes.