The clearance of nanoparticles (NPs) by mononuclear phagocyte system (MPS) from blood leads to high liver and spleen uptake and negatively impacts their tumor delivery efficiency. Here we systematically evaluated the in vitro and in vivo nanobio interactions of a two-dimensional (2D) model, gold (Au) nanorings, which were compared with Au nanospheres and Au nanoplates of similar size. Among different shapes, Au nanorings achieved the lowest MPS uptake and highest tumor accumulation. Among different sizes, 50 nm Au nanorings showed the highest tumor delivery efficiency. In addition, we demonstrated the potential use of Au naonrings in photoacoustic imaging and photothermal therapy. Thus, engineering the shape, surface area, and size of Au nanostructures is important in controlling NP–MPS interactions and improving the tumor uptake efficiency.