<p>This paper argues that the concept of intrinsic motivation has been used by economists in inconsistent ways because the underlying theories of intrinsic motivation, imported into economics from psychology, are competing and mutually exclusive despite employing the same terminology. I first identify and analyze three distinct economic accounts where intrinsic motivation refers to different things due to different underlying psychological theories employed. I then discuss implications these differences have for empirical work and incentive-based policy interventions. Finally, I use this discussion as a case study to demonstrate the shortcomings of the recently proposed pragmatic synthesis between neoclassical and behavioral economics. If there are multiple and fundamentally different psychological theories of the same phenomenon, using their insights in economic analysis is hardly just a matter of a straightforward pragmatic choice among the various tools in the economist’s toolbox.</p>