In the context of chronic disease, models and studies in health psychology have first focused on the patients鈥?adjustment. Research conducted with the Transactional Model of Stress and Coping () and the Transactional Integrative and Multifactorial Model () have shown that individuals鈥?social relations, and especially family support, are associated to patients鈥?outcomes. Recently, studies have taken more attention to the 鈥渟ignificant others鈥? most often the partners. In fact, relatives are also affected indirectly by the disease and its changes on daily life. Moreover, they often play a crucial role by helping the patient to face the disease. These models are focused on the individual and are not relevant to study dyads. An evolution of these models can be proposed by integrating a systemic and dyadic approach. In fact, the way the patient and the relative face the disease, the quality of their relation but also the way they face the disease together, as a dyad, have to be considered. The first part of this article presents the Transactional Model of Stress and Coping and the Transactional Integrative and Multifactorial Model and their evolutions. The second part shows how it is possible to develop a dyadic approach based on these models. It presents the Family System-Illness Model (), the Developmental-Contextual Model of couples coping with chronic illness across the adult life span () and a Systemic and Transactional Model of Dyads, which help to take more completely into account the adjustment processes of patients and relatives to a chronic illness.