Introduction: Long non-coding RNA (lncRNA) NCK1-AS1 could regulate multiple cancer progression. However, little is known regarding the roles and acting mechanisms of NCK-AS1 in gastric cancer (GC) progression. This work was aimed to explore the relationship between NCK1-AS1 and GC progression to illustrate the mechanisms of NCK1-AS1. Methods: NCK1-AS1 expression level in GC tissues and cells was measured with a quantitative real-time PCR method. In vitro experiments including cell counting kit-8 assay, colony formation assay, wound-healing assay, and transwell invasion assay were employed to detect biological roles of NCK1-AS1 in GC progression. In vivo experiments were performed to analyze the roles of NCK1-AS1 on GC malignant phenotype. Moreover, mechanisms behind the biological roles of NCK1-AS1 in GC were investigated using bioinformatic analysis, luciferase activity reporter assay, RNA immunoprecipitation assay, and rescue experiments. Results: NCK1-AS1 was found to have elevated expression in GC tissues and cells in comparison with normal counterparts. Loss-of-function experiments showed knockdown of NCK1-AS1 refrained GC cell proliferation, colony formation, migration, and invasion in vitro. Animal experiments showed silence of NCK1-AS1 suppresses tumor growth in vivo. Functionally, NCK1-AS1 serves as a sponge for microRNA-137 (miR-137) to upregulate nucleoporin 43 (NUP43) expression in GC. Rescue experiments proved the carcinogenic role of NCK1-AS1/miR-137/NUP43 axis in GC progression. Discussion: In conclusion, the NCK1-AS1/miR-137/NUP43 axis was identified that could contribute to GC malignancy behaviors.