Caregivers play an essential role in supporting cancer patients through their experiences, but little research explores caregiver involvement in treatment decision-making. Research demonstrates lower caregiver involvement is associated with higher regret and conflict among cancer patients, though this research primarily has been qualitative (Katie Lee & Knobf, 2016). This study examined the relationship between caregiver involvement in treatment decisions and patient-related decisional outcomes of satisfaction, regret, and conflict. We hypothesized that a greater level of caregiver involvement in treatment decision-making will be associated with patients’ greater satisfaction and lower regret and conflict. Patients receiving treatment for lung cancer (N=21) reported their caregiver’s involvement in lung cancer treatment decision making, which was then coded (involved or not involved) from semi-structured patient interviews. Patient decisional outcomes were measured using the Satisfaction with Decision Instrument, Decision Regret Scale, and SURE test of decisional certainty.