The steady‐state photoconductance and the transient photoresponse of boron‐doped polycrystalline silicon films have been measured as a function of intensity at photon energies above and below the band gap applying several semiconductor lasers. The intensity dependence of the dc photosignal and the transient behavior are distinctly different for interband and subgap excitation. A kinetic model taking into account grain boundary as well as bulk carrier generation and recombination has been developed describing the observed nonlinear and transient effects consistently. The experimental results yield the density of occupied and unoccupied trap states, absolute values for the optical absorption cross section and thermal capture cross sections and relaxation time constants.