Let K be a field of prime characteristic p and let G be a finite group with a Sylow p -subgroup of order p. For any finite-dimensional K G-module V and any positive integer n, let L"( V) denote the nth homogeneous component of the free Lie K-algebra generated by (a basis of) V. Then L n ( V) can be considered as a K G-module, called the nth Lie power of V. The main result of the paper is a formula which describes the module structure of L"( V) up to isomorphism.