Background: End-of-life conversations are rarely initiated by care staff in long-term care facilities. A possible explanation is care staff's lack of self-efficacy in such conversations. Research into the determinants of self-efficacy for nurses and care assistants in end-of-life communication is scarce and self-efficacy might differ between care staff of mental health facilities, nursing homes, and care homes. This study aimed to explore differences between care staff in mental health facilities, nursing homes, and care homes with regard to knowledge about palliative care, time pressure, and self-efficacy in end-of-life communication, as well as aiming to identify determinants of high self-efficacy in end-of-life communication. Methods: Two cross-sectional Dutch studies, one in mental health facilities and one in nursing and care homes (PACE study). Nurses and care assistants were invited to complete a questionnaire in 2015. Multivariable logistic regression analyses were performed to identify determinants of high self-efficacy. Results: Five hundred forty one nurses and care assistants completed a survey; 137 worked in mental health facilities, 172 in nursing homes, and 232 in care homes. Care staff at mental health facilities were the most knowledgeable about the World Health Organization's definition of palliative care: 76% answered 4-5 out of 5 items correctly compared to 38% of nursing home staff and 40% of care home staff (p < 0.001). Around 60% of care staff in all settings experienced time pressure. Care staff had high self-efficacy regarding end-of-life communication with patients: the overall mean score across all facilities was 5.47 out of 7 (standard deviation 1.25). Determinants of high self-efficacy were working in a mental health facility, age > 36, female, with formal palliative care training, and knowledge of the palliative care definition. Conclusion: Mental healthcare staff knew more about palliative care and had higher self-efficacy in end-of-life communication compared to nursing and care home staff. Educating care staff about providing palliative care and training them in it might improve end-of-life communication in these facilities.