Purpose: This study was done to explore time management behavior and self-efficacy in nursing students and to analyze the correlations between time management behavior and self-efficacy. Methods: The data were collected from May 12 to 20 2010 using self-report questionnaires about time management behavior and self-efficacy of nursing students. The data from 508 students were analyzed using descriptive analysis, K-means clustering, and one-way ANOVA. Results: The mean score for time management behavior was 3.03${pm}$1.11 out of a possible 5, and self-efficacy was 3.65${pm}$0.42 out of a possible 6. Four groups were identified according to time management behavior. The four groups were significantly different on self-efficacy total (p=<.05) and self-regulatory efficacy (p=.<005). The group with the highest score for time management had the highest score for self-efficacy. Conclusions: The results of the study indicate that time management behavior styles are related to self-efficacy for nursing students. Therefore, time management education programs based on the time management behavior styles are needed to increase self-efficacy in nursing students.