There is growing recognition of the importance of advising support for ensuring student postsecondary success--especially for disadvantaged students. This resource provides an overview of the extensive theoretical and empirical research base on student advising and confirms that there is promising evidence that advising can benefit students. Numerous studies reviewed for this resource also suggest that the nature, timing, and intensity of advising matters. Yet few of these studies have used research designs that satisfy the rigorous evidence criteria required by the Every Student Succeeds Act (ESSA). Future research, using more rigorous designs, is needed to refine our understanding of the merits of different advising approaches, and to increase the rigor of the evidence base supporting this important practice. [Great Lakes Comprehensive Center at American Institutes for Research assisted in producing this report.]