The 2D nuclear magnetic resonance diffusion-relaxation experiment (NMR ) has proven to be a powerful method to characterize complex fluids. Molecular components with distinct diffusion coefficients are shown on maps as separate peaks. In porous media such as reservoir rocks, molecular diffusion is restricted such that the apparent diffusion coefficient is time dependent and the diffusion behavior is non-Gaussian. Such restricted diffusion effects can manifest on the maps and complicate the interpretation of the results, but so far, they have not been systematically investigated. We used controlled laboratory experiments to demonstrate the influence of non-Gaussian restricted diffusion on NMR maps under various conditions and to show how restricted diffusion effects on maps can be distinguished from multiphase fluids. NMR experiments were carried out on a series of water-saturated packs of glass beads and two rock cores. The results revealed the important role of two critical length scales controlling the restricted diffusion effects on NMR maps: the molecular diffusion length during the NMR diffusion encoding time and the characteristic pore size . For , the effect of non-Gaussian diffusion was negligible and the NMR map showed only one peak. As approaches , an additional peak with a smaller diffusion coefficient emerged (resembling the map of an unrestricted two molecular components fluid), and its relative intensity was maximized (to ), when . As further increased, the relative intensity of the additional peak started decreasing, in contrast to the scenario of maps of multiphase fluids. We determined the extent and influence of restricted diffusion on NMR maps, and we informed the interpretation of NMR measurements, which are commonly used to quantify gas, water, and oil signals in reservoir rocks.