Background and objectiveCritical thinking is a crucial skill in nursing that nursing students should apply in their work environment. It involves analyzing, evaluating, and interpreting information. It is used in various topics such as disease diagnosis, treatment planning and implementation, monitoring, and evaluation of results, problem-solving, and decision-making in emergencies. This study in Iran aimed to evaluate factors associated with nursing students' critical thinking ability.Study methodFollowing the STROBE guidelines, an analytical cross-sectional study was conducted in Ardabil province, northwest Iran. The study collected data through convenience sampling at nursing schools in Ardabil province, with a sample of 246 nursing students participating. The data collected from a demographic information form and the Persian version of the Nursing Critical Thinking in Clinical Practice Questionnaire were analyzed using SPSS version 22.0 software.ResultsThe study found that the overall mean score of clinical critical thinking among nursing students was 313.87 ± 25.80 (range = 109–436). Based on this score, most students reported low (63%) or moderate (37%) clinical critical thinking levels. The highest and lowest mean scores between dimensions were related to the intellectual and cognitive (127.99 ± 13.30) and technical (17.25 ± 3.43), respectively. Multiple linear regression analysis revealed that semester and college were predictors of clinical critical thinking among nursing students. The selected predictors accounted for 19.3% of the total variance in clinical critical thinking scores (F = 9.396, p < 0.001).ConclusionThe study results showed that nursing students could have performed better in critical thinking ability. The study suggests that nursing education programs should prioritize teaching critical thinking skills in clinical settings as it is an essential subject in nursing education. With significant changes in nursing clinical environments, enhancing clinical critical thinking can improve nursing student performance clinically. Therefore, one of the crucial learning objectives in a clinical nursing course is to develop clinical critical thinking skills for nursing students.