Deception can be advantageous to a deceiver when the truth conflicts with his or her goals - be they personal or social, selfless or selfish. Thus it is that people regularly use deception to avoid conflict with others, to avoid punishment or embarrassment, to fit into a group, to harm, protect or help others, and for material or non-material benefit to themselves. While there are many ways in which people can deceive, for example, by choosing to fabricate rather than to tell a half-truth, there are always cost-benefit trade-offs, regardless of the strategy a person chooses. Understanding why people deceive in everyday life situations, how they do it, why they choose one strategy over another, and why sometimes they might choose not to deceive at all, even in the absence of any serious anticipated cost, will enable us to build richer models of socially intelligent behavior--models that could be employed in computational systems designed to facilitate enterprises such as elder care, tutoring, and professional training. In this workshop, we aim to address three basic questions: (1) what factors lead people to deceive? (2) what makes them decide to deceive one way rather than another? and (3) how can we model these factors computationally?