This brief defines school capacity as the presence of characteristics needed to support the development of a thriving learning community. The literature on school improvement suggests that a school's capacity for improvement can be supported by coherent structures, constructive teacher and leadership practices, and positive staff perceptions of their own efficacy and that of their students. Sufficient planning time and resources, a coordinated instructional program, teacher commitment to educating diverse students, and collective professional efficacy are among those characteristics the literature proposes to be linked with the likelihood that schools may be able to pursue improvement strategies effectively. Together, these characteristics suggest four areas or dimensions that contribute to building capacity: (1) bringing focus; (2) leading change; (3) developing accountability; and (4) creating community. [This research brief is based on the literature review "A Review of the Literature about School Capacity," which is included in Measure of School Capacity for Improvement (MSCI) User Manual and Technical Report, by Georgia K. Hughes, Lisa D. Copley, Caitlin W. Howley, and Merrill L. Meehan; and on literature reviews conducted for Edvantia by Joy Runyan and Michael T. Carter.]