Synthesis of ligand-functionalized nanomaterials with control over size, shape, and ligand orientation facilitates the design of targeted nanomedicines for therapeutic purposes. DNA nanotechnology has emerged as a powerful tool to rationally construct two- and three-dimensional nanostructures, enabling site-specific incorporation of protein ligands with control over stoichiometry and orientation. To efficiently target cell surface receptors, exploration of the parameters that modulate cellular accessibility of these nanostructures is essential. In this study, we systematically investigate tunable design parameters of antibody-functionalized DNA nanostructures binding to therapeutically relevant receptors, including the programmed cell death protein 1, the epidermal growth factor receptor, and the human epidermal growth factor receptor 2. We show that, although the native affinity of antibody-functionalized DNA nanostructures remains unaltered, the absolute number of bound surface receptors is lower compared to soluble antibodies due to receptor accessibility by the nanostructure. We explore structural determinants of this phenomenon to improve efficiency, revealing that receptor binding is mainly governed by nanostructure size and DNA handle location. The obtained results provide key insights in the ability of ligand-functionalized DNA nanostructures to bind surface receptors and yields design rules for optimal cellular targeting.