Colon cancer is the third most common malignant tumor and its mortality rate ranks fourth among all malignant tumor types. Bioinformatics analysis has shown that GSPT1 is dysregulated in colon cancer and is associated with tumor progression. However, the underlying mechanism remains unclear. To address this research gap, we examined the impact of GSPT1 on cell proliferation, apoptosis, migration, and invasion in vitro as well as tumor growth in vivo in colon cancer by using a Cell Counting Kit-8 assay, flow cytometry, transwell migration assay, transwell invasion assay, and tumor xenograft model-based analysis, respectively. GSPT1 was significantly up-regulated in colon cancer tissues and cell lines. High GSPT1 expression was correlated with a larger tumor size. Depletion of GSPT1 suppressed cell proliferation, migration, and invasion-induced colon cancer cell apoptosis in vitro and restrained tumorigenicity in vivo in HCT116 colon cancer cells. Taken together, our findings suggest that the GSPT1/GSK pathway exerts tumor-promoting actions in colon cancer oncogenesis and progression. The GSPT1/GSK pathway may thus be an effective target for controlling colon cancer.