In recent years, there has been an explosion in the growth of mobile learning across all sectors of education. Keen interest in mobile learning has led to a proliferation of views, perspectives, and diverse activities underpinned by different learning theories. This chapter focuses on various dimensions of mobile learning, including definitions, theoretical dimensions, mobile learning applications in higher education, and future research directions. Mobile learning is still an emerging and immature field. The chapter provides broad definitions and discussions of mobile learning drawing upon existing work. By exploring the experiences and views of various researchers, the chapter reveals the opportunities and challenges involved with mobile learning.