Inorganic nanoparticles (NPs) are useful materials in the chemical, physical, biological, and medical sciences. Biomedical applications require inorganic NPs to be stable in hydrophilic environments and to avoid premature biodegradation or clearance by the immune system. For this, the NP surface is engineered to enable NP colloidal stability, biocompatibility, and biomedical function. In this review, we present recent advances in polymer coatings of inorganic NPs focusing on polymer composition, ligand architecture, and the resulting coating properties. Further, we discuss how engineering of the polymer coatings governs the NP physicochemical and biological properties, enabling biomedical use as therapeutics, diagnostics , biosensors, and building blocks for material assembly.