Purpose: This study investigates the effects of self-study circle activity on self-directed learning ability and learning attitude in nursing students. Methods: This research design is modeled on a nonequivalent control group pretest-posttest design conducted on 36 nursing students (exp.: 21, con.: 15). Data collection was performed from March 2 to July 20, 2013. Data were analyzed using ${chi}2$-tests and t-tests via the SPSS Win 12.0 program package. The variables were self-directed learning ability and learning attitude. Results: The experimental group revealed significant differences in self-directed learning ability (p<.05) and physiology grade (p<.01) relative to the control group. In contrast, no significant differences between learning attitude were manifest between the two groups. Conclusion: It confirmed that study circle activity is effective in increasing self-directed learning ability in nursing students.