Engineering polymers are materials with superior structure–property correlations. They have exceptional mechanical properties such as strength, stiffness, creep, and dimensional stability, which are further complemented by superior thermal stability, flame retardancy, and the like. These properties enable the use of the engineering polymers in specific, high-end applications in automotive and aerospace industries. This chapter reviews recent advances in the synthesis, modification, and characterization of a large variety of engineering polymers such as polysulfones, polyimides, poly(phenylene oxide), aramids, polysulfides, polyketones, liquid crystalline polymers, and poly(phenylene ether)