To investigate the role of CEP55 in the occurrence and development of oral squamous cell carcinoma (OSCC). Through the utilization of the online OSCC database and bioinformatic analysis, we examine CEP55 expression and its correlation with prognosis, pathways, and immune infiltration. CEP55 and other biomarkers were stained using immunohistochemical methods in 57 cases of OSCC and 44 cases of adjacent paired tissues, demonstrating the clear involvement of CEP55. The expression levels of CEP55 were significantly higher in OSCC tissues compared to normal tissues. Additionally, higher levels of CEP55 were associated with a worse prognosis. CEP55 expression levels were significantly higher in OSCC tissues compared to normal tissues. Additionally, higher levels of CEP55 were associated with a worse prognosis. GSEA results indicated a correlation between CEP55 and the cell cycle. Immunohistochemical staining revealed a significant positive correlation between CEP55 and cell cycle-related protein markers (PCNA, P16, P21, and P53). Furthermore, CEP55 was found to significantly inhibit tumor immune infiltration. As a result, CEP55 expression decreased infiltration of 9 types of immune cells (iDC, mast cells, pDC, DC, Th17 cells, TFH, Treg, T cells, and neutrophils), while increasing infiltration of only 3 types of immune cells (Tcm, T Helper cells, and Th2 cells). The results suggest that CEP55 plays a crucial role in the progression of OSCC promoting cell cycle progression and suppressing immune infiltration.