PURPOSE The proportion of patients with advanced cancer who receive outpatient specialty palliative care (OSPC) is as low as 2.0%. Improved understanding of the system-level factors influencing use of OSPC could inform adaptations to the delivery of palliative care to maximize access. We examined associations between OSPC use among patients with advanced solid tumors and oncology-OSPC clinic colocation and patient travel time to an OSPC clinic. PATIENTS AND METHODS We conducted a retrospective cohort study of patients with advanced solid tumors receiving oncologic treatment between January 1 and December 31, 2016, within a comprehensive cancer center network with well-established, oncology-specific OSPC clinics. Multivariable logistic regression analysis was used to evaluate the associations of clinic colocation and geographic access with OSPC use. RESULTS Of 9,485 patients with advanced solid tumors, 478 (5.0%) received OSPC services in 2016. After controlling for age, sex, marital status, cancer type, insurance, treatment intent, and illness severity, patients whose oncologist practices were colocated with OSPC clinics were more likely to use OSPC (odds ratio [OR], 19.2; 95% CI, 14.1 to 26.2). Compared with patients who lived . 90 minutes from an OSPC clinic, patients with travel times of, 30 minutes (OR, 3.2; 95% CI, 2.2 to 4.6) and 31 to 60 minutes (OR, 2.4; 95% CI, 1.6 to 3.6) were also more likely to use OSPC. CONCLUSION Among patients with advanced solid tumors, colocation of oncology and OSPC clinics and shorter patient travel time were associated with greater odds of using OSPC. Future efforts to increase OSPC use in this population should consider clinic colocation and travel burden.