Gastric cancer (GC) has been one of the most leading cause of cancer-death worldwide. Long non-coding RNAs (lncRNAs) have been found to be related with the carcinogenesis and the development of various cancers, including GC. However, there are still many GC-related lncRNAs functional roles and molecular mechanisms that have not yet been clearly studied. Herein, we report lncRNA CCDC144NL-AS1, which has not been explored in GC, and it is markedly upregulated in GC tissues, which may serve as an independent predictor of poor prognosis. We found that CCDC144NL-AS1 expression was significantly positively associated with a larger tumor size and more pronounced lymph node metastasis. Through a series of in vivo and in vitro functional experiments, we observed that CCDC144NL-AS1 could facilitate cell proliferation, invasion and migration and inhibit cell apoptosis in GC. Further mechanism investigation revealed that CCDC144NL-AS1 acted as a competing endogenous RNA (ceRNA) for sponging miR-143-3p and upregulated the expression of its direct endogenous target MAP3K7 in GC. Taken together, our results elucidate the oncogenic roles of CCDC144NL-AS1/miR-143-3p/MAP3K7 axis in GC progression, providing inspiration for further understanding of the mechanism of GC and making CCDC144NL-AS1 as a potential novel diagnostic and therapeutic target for GC.