As agile methods' popularity continues to grow, massive information and feedback on how these frameworks have been adopted can be found both in academia and industrial knowledge bases. Based on such collective experience, many approaches have been proposed aiming at simplifying the agile adoption process and maximizing its chances of success. These approaches guide practitioners by providing steps to follow to find out which practice 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 to make reusable and systematic that knowledge and experience on agile adoption reported in literature. Based on this model, added knowledge and inference rules, practitioners will systematically be able to get the answer with respect to agile practice selection and adoption, 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.