Background: Nursing informatics refers to a specialty in nursing that influences the learning environment, interprofessional collaboration, patient care, strategic planning, and patient satisfaction. Nursing informatics competency has been identified as a critical factor influencing the quality-of-care services. Nurses must integrate informatics into clinical decision-making processes. Objectives: This study aims to conduct a comparative analysis of nursing informatics competency among nursing educators, students, and clinical nurses. Methods: This descriptive-analytical study was conducted in 2023 at the nursing faculty of Abadan University of Medical Sciences. The study sample included 670 participants: Nursing educators, students, and clinical nurses. Nursing educators and students were selected through a census method, while clinical nurses were chosen via random sampling. Data were collected using the Nursing Informatics Competency Assessment Tool (NICAT) and demographic questionnaires. The NICAT assesses informatics competency across 30 components, categorized into three dimensions: Computer literacy, informatics literacy, and information management skills. Data were analyzed using SPSS version 26 software. Results: The average nursing informatics competency score among the participants was 105.58, falling within the competent range. Nursing educators achieved the highest competency score (110.21), followed by clinical nurses (106.24) and students (103.78). The highest score was observed in informatics literacy (45.84), while the lowest score was seen in information management skills (24.59). Information management skills, computer literacy, and informatics literacy were significantly correlated with the overall nursing informatics competency score (P < 0.001). Conclusions: Nursing educators, students, and clinical nurses were found to be competent in nursing informatics. However, due to technological advancements and the growing use of electronic health services, there is a need to enhance nurses' competencies in all dimensions, particularly in information management skills. It is recommended to revise the curriculum and provide the necessary infrastructure and equipment to integrate informatics into nursing education and empower nurses.