Nanomedicine is now a well-established field of research that is generating a lot of enthusiasm because of its great potential to improve current treatments and enable better diagnosis of many diseases. Most of the current treatments for severe diseases (e.g., cancer) are based on small molecule therapeutics. However, they still face significant limitations and issues such as the occurrence of severe secondary effects due to off-target toxicity, potential early degradation and difficulties in administering poorly soluble drugs. To address these therapeutic challenges, drug-loaded nanocarriers are being extensively studied for their many advantages, such as their ability to prevent early drug release and/or degradation, to allow delivery of poorly soluble drugs, to induce more precise targeted delivery to diseased tissues and cells, and to enable combination therapy. Since the lipid vesicles reported in the 1960s, various families of nanocarriers have been developed, such as liposomes, micelles, nanoparticles or polymersomes, covering a wide range of materials (e.g., organic, inorganic, biological). Among them, the use of polymers is very popular in the construction of nanocarriers due to their great diversity in nature and properties. Aliphatic polyesters, synthetic polypeptides and natural carbohydrates have long been considered as reference polymers in this field. However, vinyl polymers have received increasing attention as building blocks for nanocarriers, especially since the advent of reversible deactivation radical polymerization (RDRP) techniques, such as nitroxide-mediated polymerization (NMP), atom-transfer radical polymerization (ATRP) and reversible addition-fragmentation chain transfer (RAFT) polymerization, which allow for synthesis of tailor-made polymer architectures. Vinyl polymers offer numerous advantages such as: (i) their great versatility (e.g., size, nature, composition, properties); (ii) the possibility to obtain nanoparticles with various morphologies (e.g., spherical, vesicular, rod-like, core-shell) (iii) as well as their ease of synthesis and functionalization, which allows for easy implementation of stimuli-responsiveness for greater therapeutic efficacy and for the grafting of biologically active and/or imaging agents for "theranostic" purposes (i.e., to combine therapeutic and imaging modalities). In addition, long criticized for their non-degradability which can lead to deleterious side effects when used in vivo, vinyl polymers can now be efficiently made (bio)degradable thanks to advances in radical ring-opening polymerization (rROP). Polymer prodrug nanoparticles, which rely on coupling drugs to the polymer via cleavable linkers, have been widely studied as drug delivery systems capable of addressing problems associated with traditional drug-loaded polymer nanoparticles based on physical drug encapsulation. Indeed, the covalent linkage between the drug and the polymer transiently inactivates the drug until it is cleaved, preventing the "burst release" effect from occurring, which can be toxic to patients. Such approach also increases the compatibility of the drug with the polymer matrix and can lead to high drug loadings. Polymer prodrugs therefore allow for improved solubility of poorly soluble drugs and increase their blood circulation time for prolonged drug exposure.