Abstract Gastric cancer (GC) is a global health problem and further studies of its molecular mechanisms are needed to identify effective therapeutic targets. Although some long noncoding RNAs (lncRNAs) have been found to be involved in the progression of GC, the molecular mechanisms of many GC-related lncRNAs remain unclear. In this study, a series of in vivo and in vitro assays were performed to study the relationship between FAM225A and GC, which showed that FAM225A levels were correlated with poor prognosis in GC. Higher FAM225A expression tended to be correlated with a more profound lymphatic metastasis rate, larger tumor size, and more advanced tumor stage. FAM225A also promoted gastric cell proliferation, invasion, and migration. Further mechanistic investigation showed that FAM225A acted as a miR-326 sponge to upregulate its direct target PADI2 in GC. Overall, our findings indicated that FAM225A promoted GC development and progression via a competitive endogenous RNA network of FAM225A/miR-326/PADI2 in GC, providing insight into possible therapeutic targets and prognosis of GC.