Lean management is considered one of the most effective quality improvement approaches used in healthcare organizations to improve efficiency, eliminate waste, and enhance patient outcomes. Despite the increasing use of lean strategies in healthcare settings, several organizational and staff-related barriers negatively affect successful lean implementation. Aim: This study aimed to assess barriers affecting lean management implementation among nursing staff working in intensive care units at King Khalid Hospital, Najran, Saudi Arabia. Design: A descriptive exploratory research design was utilized. Setting: The study was conducted at King Khalid Hospital, Najran, Saudi Arabia. Sample: A convenient sample of 50 nurses working in intensive care units participated in the study. Tools: Data were collected using: (1) a personal and work-related characteristics questionnaire, (2) a lean management knowledge questionnaire, and (3) a lean implementation barriers assessment questionnaire. Results: All participants demonstrated low levels of lean management knowledge. The highest perceived barriers were heavy workload and staff shortage (2.91 ± 0.27), lack of training programs (2.88 ± 0.31), resistance to change (2.75 ± 0.42), lack of resources and equipment (2.71 ± 0.39), and inadequate leadership support (2.69 ± 0.45). Conclusion: Several organizational and individual barriers negatively affect lean management implementation among nursing staff in intensive care units. Continuous education, leadership support, and staff involvement are essential for successful lean implementation. Recommendations: Healthcare organizations should provide continuous lean management educational programs, strengthen leadership support, improve staff participation in decision-making, and develop organizational strategies that facilitate lean implementation in healthcare settings.