Results are presented of a theoretical and experimental investigation of the dynamic conductivity in the microwave region of a two-dimensional lateral-surface superlattice. A theoretical analysis based on the solution of the Boltzmann kinetic equation for 2D electrons in a laterally modulating potential, an external magnetic field and a microwave field shows that the components of the dynamic conductivity tensor have an oscillatory character of various types. A preliminary experimental study of the dynamic conductivity in the microwave region is presented. Measurements of the reflection coefficient of the microwave radiation (f=38 GHz) from a GaAs/AlGaAs lateral superlattice have been carried out. For the first time Weiss-type oscillations have been observed in a dynamic regime.