The purpose of this thesis is to analyze the application of Modeling and Simulation (M&S) within the Army Operational Test and Evaluation (OT&E) process in support of weapon systems acquisition. This thesis considers the Army's current acquisition process, M&S technologies, infrastructure, and policies that guide the Program Manager (PM) in the application of modeling and simulation in operational testing. An analysis of the potential strengths and weaknesses of M&S in addressing OT&E issues is presented. Lessons learned from past OT&E efforts are analyzed for process improvement through M&S applications. The analysis indicates that M&S is a viable tool for assisting the PM in completing OT&E. M&S techniques can assist in test design validation, expand testing in areas of limited resources and environmental concerns, and validate live testing data. From this analysis, a set of recommendations are formulated, indicating where the PM can integrate M&S into the OT&E process.