Individuals are increasingly switching from hiring tax professionals to prepare their tax returns to self-filing with tax software, yet there is little research about how interacting with tax software influences compliance decisions. Using an experiment, we examine the effect of preparation method, tax software versus tax professional, on willingness to lie. Results from a structural equation model based on data collected from 211 actual taxpayers confirm the hypotheses and show individuals are more willing to lie to tax software than a (...) human tax professional. Our results also suggest this effect is jointly mediated by perceptions of social presence and the perceived detectability of the lie. Beyond the practical implications for tax enforcement, our findings broadly contribute to accounting and other literatures by examining the theoretical mechanisms that explain why individuals interact differently with computers versus humans. We also extend prior research on interactions between humans and computers by examining economically motivated lies. (shrink)