Long noncoding RNAs (lncRNAs) have been acknowledged as important regulators in various human cancers. lncRNA MNX1-AS1 has been shown to be an oncogene in epithelial ovarian cancer. However, the function of MNX1-AS1 in glioblastoma (GBM) remains largely unknown. Here we found that the expression of MNX1-AS1 was significantly upregulated in GBM tissues and cell lines. Knockdown of MNX1-AS1 significantly inhibited the proliferation, migration, and invasion of GBM cells. In terms of mechanism, we found that MNX1-AS1 could bind to miR-4443 in GBM cells. Overexpression of miR-4443 significantly inhibited the expression of MNX1-AS1 and vice versa. Moreover, there was an inverse correlation between the expression levels of MNX1-AS1 and miR-4443 in GBM tissues. We found that overexpression of miR-4443 inhibited the proliferation, migration, and invasion of GBM cells. We also showed that inhibition of miR-4443 reversed the effects of MNX1-AS1 knockdown on GBM cell proliferation, migration, and invasion. Taken together, we found that MNX1-AS1 promoted the proliferation, migration, and invasion of GBM cells through inhibiting miR-4443.