Hedgehog (Hh) pathway is important in development and cancer. Hh signaling is constitutively active in gastric cancer. Recently, tectonic 1 (TCTN1) was identified as one regulator of the Hh pathway. In the present study, the biological role of TCTN1 was examined in gastric cancer via an RNA interference lentivirus system. The constructed lentivirus efficiently suppressed TCTN1 expression in three gastric cancer cell lines. The proliferation of gastric cancer cells was significantly inhibited in TCTN1 knockdown cells, as determined by 3‑(4,5‑dimethylthiazol‑2‑yl)‑2,5‑diphenyltetrazolium bromide and colony formation assays. Furthermore, in order to determine the underlying mechanism, the cell cycle progression of MGC80‑3 cells was analyzed by flow cytometry. Knockdown of TCTN1 led to cell cycle arrest at the G2/M phase, which contributed to inhibition of growth. In conclusion, the results demonstrated that TCTN1 was essential in the growth of gastric cancer cells in vitro, suggesting TCTN1 as a potential target candidate for the treatment of gastric cancer.