We investigated high-field terahertz (THz) responses and the nonlinear conductivities of n- and p-type GaAs thin films in the THz region. As the THz pulse intensity was increased to 59 μJ/cm2, the THz transmission of the n-type GaAs thin film was significantly increased, more than that of the p-type film. This result is correlated with the conductivity of the electronic system caused by scattering processes. Intervalley scattering was dominant in n-type GaAs, whereas hot–cold hole interactions and intervalence band transitions were the main factors reducing the conductivity in p-type GaAs. In addition, we extracted the frequency-domain conductivity of the n- and p-type GaAs thin films and used the Drude–Smith model to explain non-Drude-like behavior due to high-field excitation. •High-field THz is useful to study carrier dynamics in intraband of semiconductor.•High-field carrier dynamics of n- and p-type GaAs thin films is investigated.•The dynamics of hot electrons and holes can be explained by scattering mechanisms.