Objective To investigate the clinical value of neutrophil-to-lymphocyte ratio (NLR) in predicting disease progression in patients with acute lacunar infarction. Methods According to the presence or absence of disease progression, 230 patients with acute lacunar infarction who were admitted from February 2012 to January 2017 were divided into progression group with 40 patients and non-progression group with 190 patients. Absolute neutrophil count and absolute lymphocyte count were recorded, and NLR was calculated. The receiver operating characteristic (ROC) curve was used to analyze the specificity and sensitivity of NLR in predicting the progression of acute lacunar infarction, and Pearson correlation analysis was used to analyze the correlation between NLR and modified Rankin Scale (mRS) score. Results Compared with the non-progression group, the progression group had significantly higher NLR, white blood cell count, and absolute neutrophil count and a significantly lower absolute lymphocyte count (P<0.05). NLR had an area under the ROC curve (AUC) of 0.800 at the optimal cut-off value of 3.25 in predicting progressive lacunar infarction (PLI), with a sensitivity of 85.06% and a specificity of 70.68%. The AUCs of white blood cell count, absolute neutrophil count, and absolute lymphocyte count in predicting PLI were 0.650, 0.745, and 0.615, respectively. The progression group had a significantly lower rate of good prognosis than the non-progression group (P<0.05). NLR, absolute neutrophil count, and white blood cell count were positively correlated with mRS score (P<0.05). Conclusions NLR has a certain value in predicting disease progression in patients with acute lacunar infarction and may be used as an effective indicator for prognostic evaluation.