Gliomas are common tumors that occur in the brain, accounting for 80% of all malignant brain tumors. Oligodendrocyte transcription factor 2 (OLIG2) is a key transcription factor and strongly expressed in gliomas, which drives proliferation and invasion of glioma cells. Our previous studies have shown that histone lysine (K) demethylase 6B (KDM6B) promotes glioma development. The data also showed that OLIG2 content was positively correlated with KDM6B. Based on this, we proposed that KDM6B may play biological roles by regulating OLIG2 expression. Subsequently, many experiments were performed including specific inhibitor treatment, gene knockdown, and chromatin immunoprecipitation (ChIP) array. These results indicated that inhibition of KDM6B enzymatic activity with GSK-J4 reduces OLIG2 gene expression and protein content. The KDM6B knockdown experiment yielded similar results, that is, it reduces the mRNA and protein level of OLIG2 in glioma cells. ChIP assay showed that the promoter of OLIG2 can be bound by KDM6B, which catalyzes the demethylation of H3K27me3 and increases the expression of OLIG2. This study reveals a new regulatory mechanism of OLIG2 by KDM6B, which has important implications for the future development of drugs for gliomas and other neurological diseases.