Background Although evidence-based practices are crucial for enhancing nursing abilities and patient outcomes, many nurses encounter barriers and facilitators that limit their capacity to effectively apply evidence-based practices. Self-efficacy is crucial to how nurses view and overcome these challenges. Aim This study aimed to examine the relationship between evidence-based practice facilitators and barriers and nurses' competencies, with a specific focus on self-efficacy as a mediating factor. Design A correlational descriptive design was used. Methods and tools A stratified random sampling of 350 nurses provided data for the study using structured questionnaires that assessed evidence-based practice facilitators, barriers, nurses' self-efficacy, and competencies. Results The strongest positive correlation was observed between practice competency and Knowledge (r = 0.903, p < 0.001), skills (r = 0.903, p < 0.001), and utilization (r = 0.921, p < 0.001). On the other hand, EBP barriers show significant negative correlations with attitude (r = -0.140, p = 0.009), knowledge (r = -0.114, p = 0.032), and skills (r = -0.198, p < 0.001). Conclusion The findings of this study highlight a significant mediating effect of self-efficacy on the relationship between evidence-based practice facilitators, barriers, and nurses' competencies. Nursing implications The results of this study demonstrate how critical it is to support nurses' self-efficacy to help them overcome obstacles and improve their capacity to apply evidence-based practices, which will ultimately improve nursing competence and patient care.