Objective This study aimed to verify actor and partner effects, by examining the effects of self‐esteem, relationship quality, and subjective distress on posttraumatic growth in breast cancer survivors and their spouses, and involved a structural analysis of descriptive cause‐and‐effect relationships to verify the suitability of the actor‐partner interdependence model. Methods A structured questionnaire was used to collect data from breast cancer survivors and their spouses at outpatient centers, wards, and patient meetings in 4 general hospitals in Seoul between April 13 and September 20, 2015. Data for 336 individuals (168 couples) were analyzed. The suitability of the hypothetical model was assessed via SPSS Win 21.0 and AMOS 21.0. Actor and partner effects on posttraumatic growth in breast cancer survivors and their spouses were examined. Results Self‐esteem, relationship quality, and subjective distress exerted significant actor effects, and subjective distress exerted a significant partner effect on posttraumatic growth in breast cancer survivors. Relationship quality and support exerted significant actor effects, and self‐esteem, relationship quality, and subjective distress exerted significant partner effects on posttraumatic growth in spouses. Conclusions Posttraumatic growth in breast cancer survivors was influenced by not only relationship quality and spouses' self‐ esteem but also subjective distress; therefore, solidarity between breast cancer survivors and their spouses was important and should be maintained to provide healthy relationship support and enhance posttraumatic growth. Further, health care providers should include spouses in health‐related education and involve them in interventions and family support programs for couples.