Objective: TP73-AS1 has been reported as an overexpressed oncogenic lncRNA in several types of cancer. However, these analyses of The Cancer Genome Atlas data set revealed downregulation of TP73-AS1 in acute myeloid leukemia (AML). In this study, we aimed to study the molecular mechanism between TP73-AS1 and cell proliferation in AML. Methods: Bone marrow (BM) samples were obtained from 50 AML patients and 50 healthy controls. Cell transient transfections were performed to analyze gene interactions. Dual-luciferase reporter assay, quantitative polymerase chain reaction and western blot were used to study the gene expressions. Cell proliferation was analyzed by CCK-8 method. Results: TP73-AS1 was confirmed to be downregulated in AML. TP73-AS1 was predicted to interact with miR-21, while overexpression of TP73-AS1 and miR-21 did not affect the expression of each other. Instead, overexpression of TP73-AS1 led to the upregulation of phosphatase and tensin homologue (PTEN), a downstream target of miR-21. Cell proliferation analysis showed that overexpression of TP73-AS1 and PTEN led to a decreased proliferation rate of AML cells. Overexpression of miR-21 played an opposite role and reduced the effects of overexpressing TP73-AS1 and PTEN. Conclusion: TP73-AS1 may regulate the miR-21/PTEN axis to affect cell proliferation in AML.