Mobile devices are used more and more frequently by society. In recent years has increased the sale of those devices and therefore in the applications provided to the users. The educational apps are one of the most important, because they offer more significant opportunities for development and growth to society, developing in various areas. In this context, usability becomes a key factor for its adoption.The objective of this paper is to identify which are the usability methods that are used in mobile educational applications by subject area. Therefore, a systematic mapping review was conducted. A total of 1503 studies were identified, and only 174 were selected for this review. The results show that the user test is the most widely used usability evaluation method in mobile educational applications, and the preferred learning topics are foreign languages and information and communication technologies. These results can guide experts and developers to construct usable mobile educational apps by selecting the usability evaluation methods according to the learning topic.