High-quality end-of-life communication between healthcare professionals (HCPs), patients and/or their family caregivers (FCs) improves quality of life and reduces non-beneficial care at the end of life. Nursing homes (NHs) are among the contexts at the forefront of these conversations. Having a solid theoretical basis for the role of end-of-life communication in NHs in transitioning to palliative-oriented care can offer indications for research, practice, education, and policy related to geropalliative care. This study aimed to develop a situation-specific theory of end-of-life communication in NHs by refining an existing theory. A four-step integrative approach was employed that included: (1) checking the assumptions for theorization; (2) exploring the phenomenon through multiple sources; (3) theorizing; and (4) reporting. All elements of the existing end-of-life communication theory in NHs were confirmed: end-of-life communication improved the understanding of FCs about their relatives’ health conditions, shared decision-making, and reflections on the desired preferences of residents/FCs for care at the end of life. Furthermore, the family environment affected the burden of FCs in the decision-making process. Finally, time and resource constraints, regulations, visitation restrictions due to the COVID-19 pandemic, and social and cultural values influenced the quality and timing of communication. The study findings confirmed the impact of the political, historical, social, and cultural context on end-of-life communication, thus providing the basis for a situation-specific theory.