The tokamak concept is the main focus of fusion reactor research using magnetically confined plasmas. Within a world wide collaboration the next major experiment in this line, ITER, is currently being build in France. Among other problems related to plasma physics, plasma rotation in tokamaks is known to be an important quantity. Within the European fusion program, a specific task force deals with various experimental, theoretical and numerical issues related to plasma rotation. The goal of this task force is to broaden the understanding of this topic and to provide better information for the ITER project. The Technical University of Graz contributes to this endeavor with numerical evaluation of neoclassical toroidal viscosity due to non-resonant magnetic perturbations. In contrast to stellarators, non-axisymmetric magnetic field perturbations in tokamaks are rather small. Thus, for a variety of regimes these perturbations can be treated within perturbation theory with respect to their amplitude. It can be shown that those quasilinear regimes of plasma rotation play an important role for reactor scale plasmas. They are strongly influenced by momentum sources driven through non-axisymmetric electromagnetic field perturbations. The computation of those momentum sources can be reduced to an evaluation of the particle flux density which can be computed through a solution of the gyrokinetic equation. Usually, plasma rotation is separated into a poloidal and a toroidal part. For both parts, analytical results can only be obtained using certain simplifying assumptions pertinent to particular transport regimes, simplified device geometry, and Coulomb collision models. This strongly limits the applicability of the analytical results and the proposed project will provide numerical modeling and further understanding of poloidal and toroidal plasma rotation. The work will be based on the existing code NEO-2 which will be upgraded in a step-by-step process. Finally, results for realistic configurations such as ITER, JET, ASDEX Upgrade and DIII-D should be obtained.