A scale-up study in education typically expands the sample of students, schools, districts, and/or practices or materials used in smaller studies in ways that build in heterogeneity. Yet surprisingly little is known about the factors that promote successful scaling up efforts in education, in large part due to the absence of empirically supported theories of scaling up. A literature for scale-up studies in education is growing but is years away from providing research-supported practices in planning and conducting these studies. Following the suggestion of Schneider and McDonald (2006) to import relevant knowledge from other fields into the scale-up literature in education, this paper examines the multisite public health and nursing literature in search of a multidisciplinary knowledge base that can inform scaling up efforts in education. Five strategies and practices identified in these literatures as critical to scaling up success are described.