Objective Researchers are interested in studying whether the quality of life (QoL) of cancer patients and caregivers is influenced by internal psychobehavioral processes (temporality and coping strategies) and the personality traits that they or their relatives experience. We examined these associations in a sample of patient‐caregiver dyads by using the actor‐partner interdependence model. Methods This cross‐sectional study involved 156 cancer patient‐caregiver dyads. The self‐reported data included QoL (Short‐Form 36), coping strategies (Brief Coping Orientation to Problems Experienced Scale), time perspectives (Zimbardo Time Perspective Inventory), and personality (Big Five Inventory). The actor‐partner interdependence model was used to test the dyadic effect individualizing actor (degree to which the individual's characteristics were associated with their QoL) and partner (degree to which the individual's characteristics were associated with the QoL of the other dyad member) effects. Results Actor effects were found for patients and caregivers: The use of positive thinking and future/present‐hedonistic perspectives were associated with higher QoL; the use of avoidance and past‐negative perspective were associated with lower QoL. Partner effects were also found highlighting the specific mechanisms of the interconnections in the patient‐caregiver dyad. The patient's QoL was higher when the caregiver used social support and experienced openness. The caregiver's QoL was lower when the patient used social support and avoidance strategies and experienced future perspective. Conclusions The examination of the relationships between individuals' QoL and their internal psychobehavioral processes and personality traits will have several applications in the routine clinical management. Individual‐level and dyad‐level interventions should be proposed: cognitive‐rehabilitation, emotional and cognitive self‐regulation for time perspectives, and personality constructs.