Wild-type p53-induced phosphatase (WIP1) is overexpressed and functionally altered in multiple human malignancies. The present study investigated its abnormal expression and dysfunctions in nasopharyngeal carcinoma (NPC) in vitro. Here, analysis of WIP1 mRNA and protein in human NPC tissues revealed that both WIP1 messenger RNA (mRNA) and protein were elevated and were correlated with NPC clinical stage and metastasis in patients. In vitro experiments further showed that WIP1 inhibition led to a decrease in the proliferative ability of NPC CNE-2 and 5-8F cells accompanied by cell cycle arrest and increased apoptosis. In addition, WIP1 knockdown inhibited the invasiveness of CNE-2 and 5-8F cells and was associated with the down-regulation of the expression of matrix metallopeptidase 9 (MMP-9) mRNA and protein. Taken together, our data demonstrate that WIP1 regulates the proliferation and invasiveness of NPC cells in vitro, and this may be correlated with its modulation of MMP-9 expression, cell cycle progression and apoptosis. WIP1 functioned as a potential therapeutic target in NPC management.