Research interest in the potential of educational technology to support young children as they learn to read has significantly increased during the last decades. These studies typically adopt a media comparison approach (comparing learning with one instructional medium vs. another instructional medium) or a value-added approach (comparing learning with a standard version vs. one with an added feature). We aimed to systematically review both types of studies on the effectiveness of educational technology for enhancing preschoolers’ early literacy development. Our systematic search in four databases resulted in 67 studies eligible for inclusion. Our analyses addressed three research questions: (a) Is educational technology effective in stimulating preschoolers' early literacy development? (b) Which features of educational technology and its implementation are associated with its effectiveness? (c) Which child-related characteristics are associated with its effectiveness? Results show that the media comparison studies provide some evidence for the effectiveness of educational technology in early literacy instruction, but supported by medium to large effect sizes for only part of the studies. Moreover, features of educational technology and child-related characteristics were less frequently investigated, with a small number of studies per investigated feature or characteristic. The small number of studies and limited availability of effect sizes does not allow to draw strong evidence-based conclusions related to these research questions. Future studies are needed to deepen current insights into the effectiveness of educational technology for early literacy instruction, and especially the contribution of specific educational technology features and child-related characteristics to its effectiveness. (author abstract)