“…We are concerned with the homogenization of the initial boundary value problem with oscillating data, referred to throughout the paper as problem (P ): du t −div (A (x) ∇u ) dt + B(t, u t )dt = f (t, x, x/ε, ∇u )dt + g(t, x, x/ε, u t )dW in (0, T ) × Q u = 0 on (0, T ) × ∂Q, u (0, x) = a (x), u t (0, x) = b (x) in Q, where u t denotes the partial derivative ∂u /∂t of u with respect to t, > 0 is a sufficiently small parameter which ultimately tends to zero, T > 0, Q is an open and bounded (at least Lipschitz) subset of R n , W = (W (t)) (t ∈ [0, T ]) an m-dimensional standard Wiener process defined on a given filtered complete probability space (Ω, F, P, (F t ) 0≤t≤T ); E denotes the corresponding mathematical expectation. For a physical motivation, we refer to [27,28], where the authors discussed real life processes of vibrational nature subjected to random fluctuations; for instance the nonlinear term B(t, u t ) stands for damping effects, the term f (t, x, x/ε, ∇u ) is the oscillating regular part of the force acting on the system and depending linearly on ∇u , while the term g(t, x, x/ε, u t )dW represents the oscillating random component of the force; it depends on u ε t . More precise assumptions on the data will be provided shortly.…”