Introduction Basilar artery occlusion (BAO) is a life‐threatening condition associated with high morbidity and mortality. The clinical effectiveness of endovascular therapy (EVT) in patients with stroke due to BAO is not well established. The objective of our study is to investigate the role of Posterior circulation Acute Stroke Prognosis Early CT Score (pcASPECTS) in predicting clinical outcome in patients with BAO who undergo EVT. Methods We conducted a retrospective analysis on 45 patients with acute BAO who received EVT from November 2015 to June 2022. Information was collected on demographic variables, medical history, clinical parameters, and CT based pcASPECTS on admission. Functional outcomes were assessed via binarization of the following variables: the modified Rankin scale score on discharge, NIH stroke scale on discharge, and the modified Rankin scale score 90 days following discharge. A series of logistic regression models adjusted for age, gender, atrial fibrillation, systolic blood pressure at admission, tPA receipt, and NIH stroke scale on admission were run to assess the association of pcASPECTS score on admission with binarized outcome measures. Results Among 45 patients (mean age 63.6+11.4 years, 73.3% males), binarized pcASPECTS score on admission (< 7: greater severity, >7: lower severity) was not shown to be significantly associated with functional outcome across a series of logistic regression models. When assessing for binarized modified Rankin scale at discharge (0‐3: good outcome, 4–6: poor outcome), a lower severity of pcASPECTS showed 5.47 times the odds of a good outcome (OR: 5.47; 95% CI: 0.17, 173.25; p‐value: 0.34). When assessing for binarized NIH stroke scale on discharge (0‐15: mild/moderate; >15: severe), a lower severity pcASPECTS showed 6.05 times the odds of a mild/moderate outcome as opposed to a severe outcome (OR: 6.05; 95% CI: 0.32, 114.62; p‐value: 0.23). When assessing for a modified Rankin scale at 90 days post‐discharge, binarized as above, a lower severity pcASPECTS showed 4.36 times the odds of a good outcome (OR: 4.36; 95% CI: 0.27, 69.40; p‐value: 0.30). Conclusions Our study revealed that pcASPECTS on admission may help predict clinical outcomes in patients receiving EVT for BAO and therefore could be used as a guide for medical and endovascular management. These findings have far‐reaching applicability but will require larger studies to confirm significant clinical benefit.