The use of outsourcing is expanding rapidly. This chapter empirically tests a model of application development outsourcing acceptance based on the technology acceptance model (TAM). TAM-suggested perceived usefulness and ease of use mediate the effects of other variables on users’ attitudes towards a technology. The model tested in this chapter suggests that perceived usefulness and ease of use of outsourcing mediate the effects of the external environment, prior outsourcing relationships, and risks on decision-makers’ attitude toward application development outsourcing. One hundred and sixty respondents to a survey sent to 3000 IT decision makers provided data to confirm the applicability of TAM and the influences of these external variables. Support for applying TAM in this alternative context was found. Three sub-dimensions of risk, project management, relationship, and employee risk emerged. Project management and employee risks along with prior relationships were found to significantly influence decision maker perceptions about application development outsourcing.