This paper presents an integrated theoretical process model for identifying , describing, and analyzing the complex escalation and de-escalation phenomena in software development projects. The approach-avoidance theory is used to integrate core elements of various escalation theories into a holistic, explanatory framework for the two phenomena. We use a process model to identify antecedent conditions, sequences of events, critical incidents, and outcomes over the course of a project. The analysis also operates at multiple levels: project, work, and environment. This highlights the recursive interactions between project, organizational work activities, and their contexts during the software project development process. By conceiving the processes of commitment escalation and de-escalation as sequences of events involving recurring approach-avoidance decision conflict, this research allows for a deeper understanding of the ambiguity and dilemma that decision makers face during project escalations and de-escalations. Our proposed model was both informed by a detailed case study that exhibits both project escalation and de-escalation conditions, and at the same time, illuminates the perspectives of various stakeholders.