Organizations invest considerable resources in the development and implementation of IT project management (IT PM) methodologies to increase productivity and quality as well as to save time, effort, and resources. However, such methodologies are often rejected outright by users. Our research analyzes the determinants of individual usage behavior in order to enable organizations to engineer IT PM methodologies that not only provide strategic benefits but also meet the needs of actual users. The existing literature, especially Triandis’ Theory of Interpersonal Behavior as well as initial case study results from a number of organizations are used to construct a conceptual model. This research model includes four dimensions: a) Value, b) workgroup influence, c) self-beliefs, and d) organizational characteristics, which are all considered to positively influence the development of the intention to use a methodology. Additionally, we find that the effect of intentions on actual usage can be weakened by an individual’s automatic behavior such as habits.