Objective To examine the protective role of relationship satisfaction on body image in women with breast cancer throughout the first year post‐surgery. Methods Seventy‐four Swiss patients engaged in a relationship filled out a questionnaire assessing body image disturbance 2 weeks, 3 months, and 1 year after surgery. A univariate latent change score model was used to analyze the evolution of body image disturbance and the contribution of relationship satisfaction to body image disturbance. Results Women who were satisfied with their relationship reported less body image disturbance than did dissatisfied women at 2 weeks post‐surgery. Being married was also associated with less body image disturbance at that time. The protective effect of these relational variables was still observable 1 year later. Changes in body image disturbance over time were explained by the negative impacts of mastectomy and chemotherapy. Conclusions How women perceive the impact of breast cancer treatment on their body may be partly determined by the quality of the relational context in which they live.