The popularity of agile methods is constantly increasing. Information and feedback on how these frameworks were adopted can easily be found in academia and industrial knowledge bases. Such a collective experience allowed the development of many approaches in the aim of simplifying the adoption process and maximizing the chances of success. These approaches provide practitioners with guidelines to help them find the practice that suits their team best. Nonetheless, these approaches are not systematic and practitioners need to go through a long process. For instance, they need to identify the important situational factors that can have a positive/negative effect on the agile practice adoption. Available experiences thus require lots of effort to be discovered. This research proposes an agile methods knowledge representation using an ontology so that the knowledge and experience on agile adoption reported in literature may be reusable and systematic. Based on this model, added knowledge and inference rules, practitioners will systematically be able to decide which practice to select and adopt, i.e, for a given goal, practitioners can retrieve which practices to achieve; from a situation, teams can tell what can be harmful and what can be useful for adopting a practice or what problems they may encounter; etc.