Engineering materials refers to the group of materials that are used in the construction of manmade structures and components. The primary function of an engineering material is to withstand applied loading without breaking and without exhibiting excessive deflection. The major classifications of engineering materials include metals, polymers, ceramics, and composites. The important characteristics of the materials within each of these classes are discussed on this page, and tables of material properties are also provided.

Metals are the most commonly used class of engineering material. Metal alloys are especially common, and they are formed by combining a metal with one or more other metallic and/or non-metallic materials. The combination usually occurs through a process of melting, mixing, and cooling. The goal of alloying is to improve the properties of the base material in some desirable way.

Metal alloy compositions are described in terms of the percentages of the various elements in the alloy, where the percentages are measured by weight.