Recently, long noncoding RNAs (lncRNAs) have emerged as new gene regulators and prognostic biomarkers in several cancers, including gastric cancer (GC). In this study, we investigate the role of lncRNA ZEB1 antisense1 (ZEB1-AS1) on GC progression. In the present study, we found that ZEB1-AS1 expression was upregulated in GC tissues and cell lines. High ZEB1-AS1 expression was significantly correlated with advanced TNM stage, lymph node metastasis, and poor overall survival in GC patients. ZEB1-AS1 suppression reduced GC cell proliferation and invasion in vitro. Tumor formation assay in nude mice showed that ZEB1-AS1 inhibition suppressed GC cell growth. Quantitative real-time PCR showed that miR-335-5p expression was downregulated and negatively correlated with ZEB1-AS1 expression in GC tissues. And miR-335-5p expression was directly regulated by ZEB1-AS1. Furthermore, we found that inhibition of miR-335-5p abrogated the suppression of proliferation and invasion of GC cells induced by ZEB1-AS1 depletion. Collectively, ZEB1-AS1 is critical for the proliferation and invasion of GC cells by regulating miR-335-5p. Our findings indicated that ZEB1-AS1 might offer potential novel therapeutic targets for GC patients.