One of the most important and evolving issues facing psychiatry and neuroscience is understanding individual susceptibility and resistance to the development of psychiatric disorders. Many of these conditions—particularly those involving conduct problems, antisocial behavior, and excessive substance use—entail deficits in impulse control and behavioral flexibility as common core features. Impulsivity as a broad construct is non-unitary and can manifest as delayed reward intolerance, impaired response inhibition, and risky decision-making. Related but distinct constructs of behavioral (in)flexibility and compulsivity often co-occur alongside the dimensions of impulsive behavior and may involve either overlapping or distinct neural circuitries. While deficits in any of these specific neurobehavioral domains may predict—or result from—substance abuse and other psychiatric illnesses, the extent to which these and dysfunctions within their underlying neural circuitry may interact to confer dispositional liability to such disorders is unclear. To this end, animal models of impulsivity and related forms of executive dysfunction may be particularly useful in elucidating their neurobiological bases and uncovering predictors of addiction liability and treatment response. In this chapter, the most common behavioral paradigms used to operationalize facets of impulsivity and behavioral flexibility in rodents will be outlined, followed by a brief overview of the neural networks implicated in such behaviors. Finally, the relationship between impulsivity and substance use/abuse will be discussed, with an emphasis on alcohol consumption. By leveraging knowledge gained from preclinical work, together with what we have learned from human clinical studies, we can move toward a more sophisticated view of facets of impulsiveness, their neurocognitive bases, and their contributions to substance use disorders—as a foundation for developing more empirically informed and effective treatment methods.