Background: The tumor suppressor role of lncRNA PTCSC3 has been reported in papillary thyroid carcinoma, our study aimed to investigate its involvement in gastric cancer. Methods: Tumor tissues and adjacent healthy tissues were collected from gastric cancer patients. Expression of PTCSC3 and lncRNA Linc-pint in these tissues was analyzed by RT-qPCR. The interaction between PTCSC3 and Linc-pint was analyzed by overexpression experiments. Cell proliferation and stemness were analyzed by CCK-8 assay and cell stemness assay, respectively. Results: PTCSC3 and lncRNA Linc-pint were both downregulated in tumor tissues than in adjacent healthy tissues of gastric cancer patients. Low levels of PTCSC3 and Linc-pint were closely correlated with poor survival. PTCSC3 and Linc-pint overexpression inhibited tumor growth and cancer cell stemness, while Linc-pint knockdown played an opposite role an attenuated the effects of PTCSC3 overexpression. Expression levels of PTCSC3 and Linc-pint were significantly correlated in tumor tissues but not in adjacent healthy tissues. Overexpression of PTCSC3 and Linc-pint upregulated the expression of each other. Conclusion: PTCSC3 inhibits tumor growth and cancer cell stemness in gastric cancer by interacting with lncRNA Linc-pint.