Background: To determine the correlation of inflammatory and platelet volume indices with the severity of stroke and 3-month clinical outcomes in patients with acute ischemic stroke (AIS) after endovascular thrombectomy (EVT). Methods: A retrospective analysis was conducted for AIS patients who underwent EVT at our hospital from 2015 to 2019. Inflammatory factors, including white blood count, neutrophil count, lymphocyte count, neutrophil to lymphocyte ratio (NLR), high-sensitivity C-reactive protein (hs-CRP), procalcitonin (PCT) and interleukin-6 (IL-6), and platelet volume indices, including platelet count (PC), mean platelet volume (MPV), platelet distribution width (PDW) and MPV/PC levels were assessed. Results were analyzed between patients with favorable and unfavorable outcomes at 3 months post-EVT. Results: A total of 257 AIS patients were included in the study. There were 86 (33.5%) patients with favorable functional outcomes at 3 months. Compared to patients with favorable outcomes, those with poor outcomes have lower lymphocyte count, higher neutrophil count and NLR levels. There were no differences in hs-CRP,PCT and IL-6 between the two groups. The correlation analysis showed that the increase in MPV, PDW, and MPV/PC was related to the high level of the NIHSS score at admission. Multivariate logistic regression analysis showed that higher NLR levels are an independent risk factor for unfavorable outcomes at 3 months (OR = 1.141; 95% CI 1.061 to 1.227, P = 0.000). Conclusions: MPV, PDW, and MPV/PC are associated with stroke severity. Higher NLR levels upon admission may predict unfavorable functional outcomes in patients with AIS after undergoing EVT.