Intracranial atherosclerotic disease (ICAD) large vessel occlusion (LVO) is responsible for up to 30% of LVO. In this study, we aimed to determine the likelihood of favorable functional outcomes (modified Rankin Scale 0-3) in acute ICAD-LVO basilar occlusion compared with embolic basilar occlusion. This is an analysis of the Posterior Circulation Ischemic Stroke Evaluation: Analyzing Radiographic and Intraprocedural Predictors for Mechanical Thrombectomy Registry in which patients with acute basilar artery occlusions from 8 comprehensive stroke centers were included from 2015 to 2021. Patients were dichotomized into with (ICAD-LVO) or without underlying ICAD (embolic). Descriptive statistics for each group and multivariate logistic analysis were performed on the primary outcome. Three hundred forty-six patients were included. There were 215 patients with embolic (62%) and 131 patients with ICAD-LVO (38%). Baseline demographics were equivalent between the 2 groups except for sex (male 47% vs 67%; P < .001), history of stroke (12% vs 25%; P = .002), and atrial fibrillation (31% vs 17%; P = .003). At 90 days, patients in the ICAD-LVO cohort were less likely to achieve favorable functional outcomes (odds ratio [OR] 0.41, 95% CI 0.22-0.72; P = .003) after adjusting for potentially confounding factors. In addition, ICAD-LVO strokes were less likely to achieve thrombolysis in cerebral infarction ≥2b (OR 0.29, 95% CI 0.14-0.57; P < .001). ICAD-LVO lesions were more likely to require stent placement (OR 14.94, 95% CI 4.91-45.49; P < .001). Subgroup analysis demonstrated favorable functional outcomes in patients who underwent stenting and angioplasty compared with failed recanalization cohort (OR 4.96, 95% CI 1.68-14.64; P < .004). Patients with acute basilar ICAD-LVO have higher morbidity and mortality compared with patients with embolic source. Lower rates of successful recanalization in the ICAD-LVO cohort support this finding. Our subgroup analysis demonstrates that stenting should be considered in patients with recanalization failure. Rates of symptomatic intracranial hemorrhage were similar between the ICAD-LVO and embolic cohorts.