We report measurements of the nonlinear refractive index, n 2 , and the nonlinear absorption coefficient, ␣ 2 , of Pb͑PO 3 ͒ 2 -WO 3 glasses. The measurements were performed using 100 fs ͑17 ps͒ laser pulses at 800 nm ͑1064 nm͒. Positive values of n 2 ϳ 10 −19 m 2 / W and negligible ␣ 2 were measured. The results show that the nonlinearity is faster than 100 fs and it is observed an increase of n 2 with the increasing of the WO 3 amount in the samples. The Boling, Glass, and Owyoung model, based on the semiclassical harmonic oscillator model, was used to predict the values of n 2 , with basis on the values of the linear refractive index of the samples.