Purpose <p>Fear of cancer recurrence (FCR) is a prominent psychological concern for breast cancer survivors and their spouses. Understanding longitudinal dyadic FCR trajectories is crucial for optimal intervention timing and follow-up. This prospective observational study was conducted to elucidate the general patterns and heterogeneity of dyadic FCR trajectories among breast cancer couples, examine mutual influences within dyads over time, and explore predictors of trajectory groups.</p> Methods <p>Three hundred forty-three breast cancer survivor-spouse dyads completed self-report questionnaires at baseline and at three subsequent follow-ups (1, 3, and 6&#xa0;months post-surgery assessments). Dyadic latent growth models and dyadic latent class growth models identified FCR trajectories.</p> Results <p>FCR trajectories in breast cancer survivor-spouse dyads showed a declining trend, which gradually attenuated over time. Higher initial survivor FCR predicted faster change in spouse FCR (<i>β</i> = 0.392, <i>P</i> = 0.016). This present study identified three distinct patterns of dyadic FCR trajectories among breast cancer survivor-spouse dyads: survivor low-spouse low declining group, survivor low-spouse high stable group, and survivor high-spouse moderate stable group. The distinct dyadic FCR trajectory groups were influenced by the survivors’ intrusive symptoms and the spouses’ neuroticism and depression.</p> Conclusions <p>These findings support the postoperative period as an optimal window for effective dyadic psychological interventions. Identifying heterogeneous FCR trajectories provides a theoretical foundation for personalized dyadic interventions.</p>