This article illustrates a comprehensive overview of polymer colloids in various aspects, including background, importance and preparation methods to fine‐tune their properties, particle morphology, particle analysis, and examples of their applications. For the preparation of polymer colloids, two general classifications, (heterogeneous) polymerization starting from monomers and nonpolymerization methods using preformed polymers as raw materials, are presented. A wide variety of preparation methods mainly based on emulsion polymerization including microemulsion and miniemulsion are given. Features of these methods and characteristics of polymer colloids obtained are also described. In fact, process operations influence the properties of polymer colloids, for example, copolymer composition, molecular weight distribution, polymer architecture, particle morphology, and particle size distribution. Thus, a summary of those process operations, that is, batch, semibatch, semicontinuous, and continuous processes, is included. Since particle morphology is of great importance for determining their properties and making them useful in a broad range of applications, the design and engineering for diversified types of structured particle are emphasized and related to their applications. Common analytical methods for particle analysis are included.