Project development success rates have improved as a result of the growing use of Agile methods in recent years. The intricacy of choosing the right approaches contributes to the difficulty of fully realizing success in projects employing Agile methods. 15 Agile experts from 10 teams in three different countries were interviewed for the study, which was carried out as a Grounded Theory investigation. The study found sixteen factors that fall into five categories and influence the selection of twenty Agile methods. These factors are grouped in accordance with the Ground Theory of Agile method selection. Agile team members can use these factors—which include project type, development team expertise, project constraints, customer involvement, and organizational culture—as a guide to determine which methods are best for various organizations and projects.