The Multi-Stage Maturity Model for Long-Term IT Outsourcing Relationship Success, a theoretical stages-of-growth model, explains long-term success in IT outsourcing relationships. Research showed the IT outsourcing relationship life cycle consists of four distinct, sequential stages: contract, transition, support, and partnership. The model was built in three steps: creation of a suggested model; creation of a conceptual model based on survey data gathered from business and IT executives, managers, and professionals experienced with long-term IT outsourcing; and advancement of the conceptual model to a theoretical model. Subject matter experts were interviewed to assess the validity and completeness of the model, which may be used to examine both sides of the IT outsourcing relationships and their progress through time. Understanding the expectations of each partner at different stages of the relationship should minimize deficiencies, misunderstandings, and mismatched foci to result in better partnerships.