Background: Critical thinking (CT) is a core competency in surgical nursing, essential for timely decision-making, patient safety, and effective teamwork. While global literature underscores the role of mentorship and experience in strengthening CT, limited evidence exists from Indian clinical contexts.

Objective: This study investigated differences in CT among surgical nurses across experience levels and examined the influence of mentorship and reflective practice in Indian tertiary hospitals.

Methods: A sequential explanatory mixed-methods design was employed. In phase one, 135 surgical nurses from two teaching hospitals in Chhattisgarh were surveyed using the California Critical Thinking Skills Test (CCTST). Participants were stratified into novice (<1-year, n=42), competent (1–5 years, n=48), and expert (>5 years, n=45) groups. Regression analysis assessed predictors of CT. In phase two, 24 semi-structured interviews explored experiences of mentorship and reflection.

Results: CT scores increased significantly with experience: novices (M=14.6, SD=2.9), competent nurses (M=18.2, SD=3.1), and experts (M=21.3, SD=3.4), F=42.56, p<0.001, η²=0.39. Mentorship exposure strongly predicted higher CT scores (β=0.41, p<0.001), with mentored nurses scoring on average 3.2 points higher. Qualitative findings highlighted mentorship as a catalyst for decision-making, reflection as a tool for clinical anticipation, and systemic barriers (e.g., workload, staffing shortages) that constrained mentoring opportunities. Integrated analysis confirmed that mentorship and reflection accelerated CT growth, particularly in early career stages.