BACKGROUND Long non-coding RNAs (lncRNAs) have been shown to be associated with many tumors. However, the specific mechanism of lncRNAs in the occurrence and development of gastric cancer (GC) has not been fully elucidated. AIM To explore the expression level and molecular mechanism of HOXD-AS2 in GC tissues and cells, and analyze its significance in the prognosis of GC. METHODS Real-time quantitative PCR was used to detect the expression of HOXD-AS2 in 79 pairs of GC tissues and five cell lines. The pcHOXD-AS2 plasmid vector was constructed and transfected into SGC-7901 and SNU-1 GC cells. Matrigel Transwell and wound healing assays were used to confirm the effect of HOXD-AS2 on invasion and migration of GC cells. Cell counting kit-8 assay and flow cytometry were used to verify the effect of HOXD-AS2 on the proliferation, cell cycle, and apoptosis of GC cells. The relevant regulatory mechanism between HOXD-AS2 and HOXD8 and PI3K/Akt signaling pathway was verified by Western blot analysis. RESULTS The low expression of lncRNA HOXD-AS2 was associated with lymph node metastasis and tumor-node-metastasis stage in GC. In vitro functional experiments demonstrated that overexpression of HOXD-AS2 inhibited GC cell progression. Mechanistic studies revealed that HOXD-AS2 regulated the expression of its nearby gene HOXD8 and inhibited the activity of the PI3K/Akt signaling pathway. CONCLUSION These results indicate that downregulation of HOXD-AS2 significantly promotes the progression of GC cells by regulating HOXD8 expression and activating the PI3K/Akt signaling pathway. HOXD-AS2 may be a novel diagnostic biomarker and effective therapeutic target for GC.© 2020 Published by Baishideng Publishing Group Inc.. All rights reserved.