The infrared thermography (IRT) technique has shown great potential with many applications in a variety of fields, such as aerospace, petroleum, civil engineering, and so forth. This chapter is designed to provide an overview of the method of IRT in non-destructive material evaluation. It begins with the general introduction and development of the IRT. It follows the basic principles of the electromagnetic spectrum and radiative energy concepts. Following the introduction of different types of thermography, applications in the non-destructive testing fields are provided. The next section focuses on recent trends and developments, in particular the integration of IRT with other technologies namely ultrasonic, acoustic emission, and so on. By assigning a data analysis section, data processing techniques are described by dividing them into two conventional and advanced categories. The numerical modeling and simulation of the IRT inspection process are then presented as beneficial applications. In addition, the relevant standards have been specified in a short separate section. To testify to the effectiveness of the IRT, a case study of a steel sample inspection is provided at the end of the chapter itself.