The neutrophil-to-lymphocyte ratio (NLR) has been demonstrated as a prognostic inflammatory biomarker in ischemic stroke. The study aimed to investigate the association of NLR and its dynamic change with long-term outcome and mortality in acute ischemic stroke (AIS) patients who received intravenous thrombolysis (IVT). From a prospective cohort, AIS patients receiving IVT (alteplase, 0.9 mg/kg) with complete NLR data were retrospectively screened. Based on 3-month modified Rankin scale score (mRS), patients were classified into good group (mRS 0-1) and poor outcome group (mRS 2-6), or survival group (mRS 0-5) and death group (mRS 6). Multivariate logistic regression analysis and receiver operating curve were used to identify prognostic factors and their predictive powers. A total of 259 eligible patients were enrolled in our study. Logistic regression analysis showed that NLR at 24 h (adjusted odds ratio aOR 1.182), 12 days (aOR 1.218) after IVT was independent predictors of 3-month outcome with the AUC of 0.815, 0.820, respectively, whereas NLR at 24 h (aOR 1.17), 12 days (aOR 1.252) after IVT and percentage changes of NLR between admission and 24 h after IVT (aOR 1.214), and between admission and 12 days after IVT (aOR 1.233) were independent predictors of 3-month mortality with the AUCs of 0.86, 0.902, 0.814, and 0.855, respectively. The comprehensive report suggests that NLR and its dynamic changes are associated with 3-month outcome and mortality in AIS patients after IVT with good predictive powers.