Objective Fear of progression (FOP) is a prevalent concern among breast cancer patients that affect their adjustment to disease. This study examined whether self‐efficacy moderates the effect of illness perception (IP) on FOP and whether the moderating effect of self‐efficacy depends on the level of depressive symptoms. Methods A cross‐sectional survey including brief illness perception questionnaire (BIPQ), FOP short form, general self‐efficacy scale, and the center for epidemiologic studies depression scale were administered to 245 patients with breast cancer in Korea. Results Self‐efficacy moderated the negative impact of the patients' perception of chronic timeline and a greater emotional impact of the illness on FOP. However, the moderating effect of self‐efficacy of the BIPQ timeline and emotions on FOP depended on level of depressive symptoms. Conclusions The findings underscore the importance of considering the IP as determinants of FOP, as well as of self‐efficacy and depression as the moderating factors in the relationship between IP and FOP, suggesting the need to enhance self‐efficacy and depressive symptoms in order to compensate the negative impact of IP on FOP in breast cancer patients.