In this review, we provide an analysis of some of the recent literature reports on the synthesis and applications of pH-responsive polymers. Depending on the solution pH, such copolymers can self-assemble and form various nanosized structures including core–shell micellar structures, micelles/reverse micelles, hollow spheres, vesicle structures, adsorbed species at the water–air interface, and more complex architectures. Their self-assembly behaviors open the door for the production of various novel nanostructures including shell/core cross-linked micelles, hollow spheres, hydrogels, microgels, layer-by-layer (LbL) nanofilms, controlled releasing systems, drug carrier systems, etc. The review consists of various major parts including types of pH-responsive polymers, synthetic methods for their synthesis and their solution behaviors, their nanostructures in aqueous media, applications as LbL nanofilms, delivery devices, controlled release systems, sensors, stabilizers, solubilizers, etc. In the last two decades, there have been great developments in synthetic methods and strategies for the preparation of novel pH-responsive polymers or polymeric materials providing possible materials for various applications including biotechnology, nanotechnology, colloid and surface science, materials science, etc.