Celecoxib is a newly-identified nonsteroidal anti-inflammatory drug, which has been used to treat fever in clinical practice. Celecoxib has been demonstrated to suppress the viability of various human tumor cells. However, the effect of celecoxib on response of T-cell lymphoma to chemotherapy agents remains unclear. The aim of the present study was to investigate the effect of celecoxib on chemosensitivity of human T-cell lymphoma, and to address the underlying mechanism of action. The cytotoxicity of CDDP, epirubicin and VCR on Jurkat and Hut-78 cells treated with celecoxib was assessed by MTT assay, and the half-maximal inhibitory concentration (IC50) value was calculated by Origin 75 software. The effect of celecoxib on apoptosis and intracellular concentration of Rhodamine-123 in Jurkat and Hut-78 cells was analyzed by flow cytometry. The expression of transcription factor p65 (p65), B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), multidrug resistance 1 (MDR1) and multidrug resistance-associated protein 1 (MRP1) at mRNA and protein levels were detected by reverse transcription quantitative polymerase chain reaction and western blotting, respectively. Proliferation suppression rates and apoptosis levels were significantly increased in Jurkat and Hut-78 cells combined with celecoxib compared with those without celecoxib, when treated with CDDP, epirubicin and VCR. The IC50 values of the chemotherapy agents were lower in Jurkat and Hut-78 cells treated with celecoxib compared with those that were not. The apoptosis level, expression of Bax and the intracellular concentration of Rhodamine-123 were increased, whereas the expression of p65, Bcl-2, MDR1 and MRP1 were decreased, in celecoxib-treated Jurkat and Hut-78 cells compared with those without celecoxib treatment. These results indicated that celecoxib may enhance the sensitivity of T-cell lymphoma to chemotherapy drugs by inhibiting the expression of multidrug resistance (MDR)-associated proteins via downregulating the activity of the nuclear factor-kappa B signaling pathway, suggesting that celecoxib may improve the curative effect of chemotherapy drugs in T-cell lymphoma.