This thesis has a twofold objective. The first objective is to characterize the Norwegian pension system before and after the pension reform scheduled to be implemented from 2010. The second and main objective is to research the long run quantitative macroeconomic and welfare effects of two counterfactual pension reforms. We focus on studying the effects of pension funding. The model frameworks we use are general and partial equilibrium overlapping generations models calibrated to Norwegian data. Consistent with the literature we find large quantitative increases in welfare and the capital stock in the new steady state as a result of pension funding under the general equilibrium model. We find marginal changes in aggregate labor supply. The partial equilibrium model is used to investigate the sensitivity of the results to the assumption of a closed economy in the general equilibrium model. The partial equilibrium model strengthens the quantitative increase in welfare and aggregate saving as a result of pension funding. Aggregate labor supply decreases strongly as a result of pension funding in the partial equilibrium model.