A concept map is a node-link diagram in which each node represents a concept and each link identifies the relationship between the two concepts it connects. We investigated how using concept maps influences learning by synthesizing the results of 142 independent effect sizes (n = 11,814). A random-effects model meta-analysis revealed that learning with concept and knowledge maps produced a moderate, statistically significant effect (g = .58, p < .001). A moderator analysis revealed that creating concept maps (g = .72, p < .001) was associated with greater benefit relative to respective comparison conditions than studying concept maps (g = .43, p <.001). Additional moderator analyses indicated learning with concept maps was superior to other instructional comparison conditions, and was effective across science, technology, engineering, and math (STEM) and non-STEM knowledge domains. Further moderator analyses, as well as implications for theory and practice, are provided. Concept maps are diagrams used in many educational settings to represent verbal or conceptual information (Figure 1). In this review we consider a concept map to be any node-link diagram in which each node represents a concept and each link identifies the relationship between the two concepts it connects. For example, if two nodes "ocean acidification" and "growth of coral reefs" are connected with a link labeled "slows" the assemblage can be read as the proposition "ocean acidification slows growth of coral reefs". A concept map can include dozens of links and nodes, with each pair of linked nodes representing a proposition. Figure 1 shows a concept map created using CmapTools, one of the more widely used software tools for authoring concept maps (Cañas et al., 2004).Diagrams similar to concept maps have been used by philosophers and logicians for centuries (Nesbit & Adesope, 2013), but the term concept map and the modern idea of the concept map as a tool for learning originated with Joseph Novak and his colleagues in the 1970s (Novak & Gowin, 1984). Novak advocates concept mapping, the construction of concept maps by learners, as a way to promote meaningful learning. He explains that concepts should be hierarchically arranged with more general concepts placed higher on the map and linked to more specific concepts placed lower in the map (Novak & Cañas, 2008). Novak further recommends that concept maps include horizontal cross-links to depict relationships other than generality/specificity. Knowledge maps, featured in research by Dansereau and colleagues (O'Donnell, Dansereau, & Hall, 2002), are node-link diagrams we consider to be a type of concept map.Instead of representing a relation between concepts by a freely chosen word or phrase, links in knowledge maps must be selected from a fixed set of nine relational terms such as "type, STUDYING AND CONSTRUCTING CONCEPT MAPS 3 "example" and "leads to". Unlike Novak's emphasis on concept mapping by learners, much of the research conducted by Dansereau examined the use of knowledge maps...