Past studies have shown that the Gelsolin-like actin-capping protein (CAPG) regulates cell migration and proliferation and is strongly associated with tumor progression. We present the first study of the mechanism of action of CAPG in early gastric cancer (EGC). We demonstrate that CAPG expression is upregulated in gastric cancer (GC) especially EGC. CAPG promotes GC proliferation, migration, invasion, and metastasis in vivo and in vitro. More importantly, CAPG plays a role in GC by involving the Wnt/β-catenin signaling pathway. Our findings suggest that CAPG may function as a novel biomarker for EGC.