In composite material modeling, numerical homogenization methods typically involve the computation of equivalent properties based on simple extension and shear modes. As a result, the computed properties cannot describe the bending behavior of composites. In this work, the equivalent flexural stiffness of heterogeneous materials is computed by applying bending/torsional boundary conditions (BCs) in the homogenization problem. Equivalent stiffness is obtained in ABD matrix form in analogy with classic laminate theory (CLT), linking force and moment resultants to strains and curvatures, respectively. The proposed methodology is applied on composites with random microstructure, whose mechanical properties exhibit random spatial variation. Taking this into account, random fields of the equivalent bending stiffness are determined using a moving window technique. The statistical characteristics of these random fields are compared to those computed for extension/shear BCs and useful conclusions are derived concerning the bending behavior of random composites.