Manufacturing devices at the microscale requires a precise analysis for desirable mechanical behavior. As the products of microscale forming operations have a comparable thickness dimension with grain size, the ratio between thickness and grain size (t/d) becomes an important aspect of mechanical behavior. A number of experimental studies investigated this phenomenon and have shown the influence of the t/d ratio in micron-sized sheet specimens. On the other hand, the computational studies addressing this phenomenon employing micromechanics-based models are quite restricted. The current study aims to investigate the t/d ratio effect through finite element method (FEM) simulations with both local and nonlocal crystal plasticity frameworks. The numerical analyses with the local crystal plasticity framework are obtained by utilizing two different methodologies, where the initial slip resistance is taken as constant or modified using a subroutine based on grain size effects and slip system interactions (see ).