On the basis of the notion that the ability to exert self-control is critical to the regulation of aggressive behaviors, we suggest that mindfulness, an aspect of the self-control process, plays a key role in curbing workplace aggression. In particular, we note the conceptual and empirical distinctions between dimensions of mindfulness (i.e., mindful awareness and mindful acceptance) and investigate their respective abilities to regulate workplace aggression. In an experimental study (Study 1), a multiwave field study (Study 2a), and a daily diary study (Study 2b), we established that the awareness dimension, rather than the acceptance dimension, of mindfulness plays a more critical role in attenuating the association between hostility and aggression. In a second multiwave field study (Study 3), we found that mindful awareness moderates the association between hostility and aggression by reducing the extent to which individuals use dysfunctional emotion regulation strategies (i.e., surface acting), rather than by reducing the extent to which individuals engage in dysfunctional thought processes (i.e., rumination). The findings are discussed in terms of the implications of differentiating the dimensions and mechanisms of mindfulness for regulating workplace aggression.