Background: Therapeutic strategies and outcomes vary with stroke subtypes for patients with acute vertebrobasilar occlusion (VBAO). This study aimed to compare characteristics and outcomes of VBAO due to intracranial atherosclerotic disease (ICAD) and embolisms and identify baseline predictors of ICAD. Methods: Patients with VBAO who received endovascular therapy (EVT) were retrospectively analyzed. Participants fulfilling the criteria were classified as the ICAD group (focal stenosis of > 70%, or fixed stenosis > 50% in addition to either flow and perfusion impairment on angiography or an evident reocclusion tendency) and the embolism group (defined as no evidence of focal significant stenosis after thrombolysis or thrombectomy). Baseline characteristics and outcomes after EVT were compared between the two groups, and logistic regression was performed to explore the factors associated with ICAD. Results: Among the 133 patients enrolled, 95 (71.4%) patients were categorized in the ICAD group, and 38 (28.6%) in the embolism group. A history of atrial fibrillation (odds ratio (OR) 0.142; 95% confidence interval (CI) (0.028-0.707), p = 0.017), distal basilar artery occlusion (OR 0.107; 95% CI (0.040-0.289), p< 0.001) and V4 segment occlusion (OR 3.423; 95% CI (1.172-9.999), p = 0.024) were independently associated with ICAD. Patients with VBAO due to ICAD had a lower rate of recanalization (81.1% vs 100%, p = 0.004), but the 90-day good clinical outcome was comparable (41.1% vs 50.0%, p = 0.347). Conclusions: The occlusion sites and a history of atrial fibrillation might be helpful in predicting ICAD in patients with VBAO. Patients with ICAD who were treated by EVT had a lower rate of recanalization but comparable 90-day good outcomes.