Governments around the world register substantial losses due to tax non-compliance behavior. Whether it is tax avoidance or tax evasion, non-compliance has repercussions on the whole society because it mitigates the quality of the provision of public goods. Nevertheless, the level of tax compliance is significantly higher than the classical tax evasion model of Allingham and Sandmo (1972) predicts. A manifold of theoretical and empirical studies invalidate the assumptions of the classical model by trying to give answers to one of the most intriguing questions: Why people pay taxes? Taking into consideration these realities, we summarize some of the findings related to tax behavior within the emerging new field of neuroeconomics. Using state-of-the-art technology (non-invasive brain stimulation, non-invasive measurement of brain activity, pharmacological interventions to raise or lower the activity of neurotransmitters, eye-tracking or skin conductance response), neuroeconomics steps on the scene to give insights on the reasons for which taxpayers display a certain tax behavior. According to the neuroeconomics mainstream literature, emotions guide the decision-making process when outcomes are uncertain with regards to rewards and losses. At neural level, the amygdala triggers bodily states related to reward and loss and the ventromedial prefrontal cortex reenacts past experiences of reward and loss to predict future outcomes. Some taxpayers who decide to engage in tax evasion experience a positive feeling when anticipating the profit from dodging taxes, feeling that is triggered by the amygdala. Other taxpayers don’t engage in tax evasion because they want to avoid negative feelings (shame, guilt, regret). Oxytocin facilitates dopamine release which is a positive physiological motivation for cooperation. As a consequence, taxpayers’ trust levels increase and, with it, increases the propensity to comply with the tax law. Besides summarizing neuroeconomics findings related to tax behavior, we also draw attention on some policy implications which may derive from neuroeconomics studies and may assist authorities in raising tax compliance levels. Tax evasion is showed to decrease in trustful environments where tax authorities facilitate compliance process and where taxpayers believe their true earnings can be accurately estimated by tax authorities. Tax evasion also decreases when tax authorities publicly denounce tax offenders.