We show that polariton effects lead to time-delayed components in the time-resolved four-wave-mixing (FWM) signal. Hence we find that recent observations in FWM experiments that have been ascribed to many-body Coulomb interactions can also be explained from the formation of exciton polaritons. In addition, we find that due to the formation of polaritons, the rate of decay of the time-integrated FWM signal strongly depends on the oscillator strength and the propagation length.