Recent studies have shown that the neutrophil-to-lymphocyte ratio (NLR) can predict short-term and long-term outcomes in acute ischemic stroke (AIS) patients. However, the relationship of the variation of NLR (ΔNLR) with hemorrhage transformation (HT) and early neurological improvement (ENI) after intravenous thrombolysis (IVT) remains unclear. This study aimed to investigate the impact of ΔNLR on HT and ENI at 24 h post-IVT and its association with different TOAST classifications. AIS patients undergoing IVT between October 2021 and October 2023 were enrolled and classified by TOAST criteria. Patients were grouped based on the presence or absence of HT and ENI. Our study demonstrated that both HT and ENI were associated with ΔNLR, which was an independent influencing factor for HT and ENI following IVT. Specifically, the ΔNLR in the small artery occlusion (SAO) group was higher than that in the minor stroke of large artery atherosclerosis (LAA) subtype. Thus, ΔNLR may serve as a useful biomarker to assist in diagnosis and monitor the outcomes of thrombolytic therapy in AIS patients.