Background: In the intensive care unit, many patients are dying despite advanced therapeutic technology and optimized treatment. The critical care team is expected to deliver end-of-life care for the dying patient and their family. However, it is challenging to provide adequate support to families due to the ideas and emotions associated with the end of life. This can be influenced by different beliefs and cultures among patients and healthcare professionals. Added to this, research about end-of-life practices in intensive care units in Saudi Arabia is limited. Therefore, this study protocol aims to examine: (1) What end-of-life care is provided by healthcare teams in adult intensive care units in Saudi Arabia? (2) What helps or hinders effective end-of-life care in adult intensive care units in Saudi Arabia? Method: This study will use a mixed-methods, sequential, explanatory design consisting of two phases. Phase 1 will include a cross-sectional study design with a convenience sample of approximately 400 healthcare providers who will be invited from three military hospitals in Saud Arabia. the Palliative and End-of-Life Care Index (PEOL Care Index) will be used to assess palliative and end-of-life care education, practice, and perceived competence among the staff. Additionally, a questionnaire on the barriers to optimal end-of-life care and the perceived benefit of potential strategies to improve end-of-life care will be applied to obtain the views of managers. Phase 2 of the study will be a qualitative descriptive design involving semi-structured interviews with healthcare providers, managers, and bereaved family members. Conclusion: The study findings will contribute to understanding current practice in relation to palliative and end-of-life care in intensive care units in Saudi Arabia. It will provide valuable insight into barriers to and facilitators of care, which will help to develop strategies and interventions to improve the quality of end-of-life practices in ICUs. In addition, this research will provide significant information regarding family members’ experiences of end-of-life care provided to their relatives.