The ability to meaningfully and critically integrate multiple texts is vital for twenty-first-century literacy. The aim of this systematic literature review is to synthesize empirical studies in order to examine the current state of knowledge on how intertextual integration can be promoted in educational settings. We examined the disciplines in which integration instruction has been studied, the types of texts and tasks employed, the foci of integration instruction, the instructional practices used, integration measures, and instructional outcomes. The studies we found involved students from 5th grade to university, encompassed varied disciplines, and employed a wide range of task and text types. We identified a variety of instructional practices, such as collaborative discussions with multiple texts, explicit instruction of integration, modeling of integration, uses of graphic organizers, and summarization and annotation of single texts. Our review indicates that integration can be successfully taught, with medium to large effect sizes. Some research gaps include insufficient research with young students; inadequate consideration of new text types; limited attention to students' understandings of the value of integration, integration criteria, and text structures; and lack of research regarding how to promote students' motivation to engage in intertextual integration.