Tectonic-1, also named as TCTN1 or TECT1, which belongs to a family of signal-sequence-containing secreted and transmembrane proteins evolutionarily conserved among eukaryotes, was reported to be involved in central nervous system development and ciliogenesis. In this paper, we found that TCTN1 is extensively expressed in human glioma cell lines. To clarify the role of TCTN1 in glioma, we employed lentivirus-mediated short hairpin RNA to knock down TCTN1 expression in U251 and U87MG glioma cells. Knockdown of TCTN1 potently inhibited cell proliferation, as determined by MTT and colony formation assays. Cell cycle analysis showed depletion of TCTN1 led to both U251 and U87MG cells arrested in the G0/G1 phase. These data suggest TCTN1 is essential for glioma cell viability, and dysregulation of TCTN1 may play a key role in glioma tumorigenesis.