The ubiquity of mobile devices, their portability and their unique gesture recognition features make them an apt educational tool, especially in the STEM fields. The traditional pen and paper practice method can be transferred to a digital format and the content can be made available to students anywhere and at any time. In this chapter the authors discuss how mobile application development projects can be used to benefit students in multiple STEM disciplines at the same time by creating a symbiotic, business-like relationship between students enrolled in a software development course and students in other STEM courses (end-users). The authors will discuss the learning needs of students and the details of thoughtful mobile application design incorporating various learning theories. This chapter will also discuss various examples of educational mobile apps created, their usability testing results and their effect on student learning.