Introduction: Patient advocacy is a central concept for the profession of nursing as it assures patient rights and safety. This article presents the findings from a study which explored the perceptions of patient advocacy from Muslim ICU nurses. Methods and participants: Our study utilized a constructivist grounded theory approach. Thirteen registered intensive care nurses from an adult critical care setting in a tertiary academic teaching hospital in Riyadh, Saudi Arabia, participated in the study. The researcher employed semi-structured interviews that were digitally recorded and transcribed verbatim, with an additional data collection strategy of reflective journaling. A reflective journal was provided to all study participants following each interview. Results: The study generated codes which connected to vulnerable patients, and subsequently identified a core category of “Caring critically” which was exemplified by six additional inter-related advocacy categories of “Essential caring”; “Vulnerable-acy”; “Familial-acy”; “Cultural-acy”; “Religion-acy”; and “Human-acy”. These categories generated the model for patient advocacy. Conclusion: The pyramid of patient advocacy can be applied in clinical practice to guide Muslim nurses, in addition to being utilized in the educational setting as a standard to teach registered nurses about the role and responsibilities of a patient advocate.