Although recent advances in polymeric nanomaterials hold promise to develop effective transdermal delivery systems, the lack of fundamental understanding of polymer–skin interactions has hindered their fast translation. In this review, we provide a comprehensive overview, focusing on the chemistry aspects of the polymeric nanomaterials, such as surface modification, hydrophilic–hydrophobic grafting, and conjugation with biodegradable polymers or links. These chemical modifications to the nanomaterials have been reported to significantly affect their interactions with skin and delivery of drugs across the skin layers. This review highlights recently developed polymeric systems based on polyester nanoparticles, polymeric micelles, dendrimers, and chitosan, which opens a new avenue through which transdermal drug delivery with high efficiency and low toxicity can be potentially achieved.