Despite a large body of research on motivation in psychology, few in information systems have related it to the information and communication technology acceptance research. This study investigates the relation between the Self-Determination Theory of Motivation and the Unified Theory of Acceptance and Use of Technology (UTAUT) Model and confirms significant relationship across the two theories. In addition, this study investigates the effect of time sequential introduction of different types of motivation and finds the presence of the negative effect between intrinsic and extrinsic motivation is conditional on the type of extrinsic motivation. Controlled extrinsic motivation undermines intrinsic motivation that precedes it, but autonomous extrinsic motivation augments such intrinsic motivation. Implications of these findings are discussed.