To test the feasibility of Wikipedia editing in large undergraduate psychology classrooms, we engaged groups of students in a large introductory-level Human Development course (N = 110) in editing Wikipedia articles to improve psychology-related content. Students attended in-class workshops and received online support to develop skills. They demonstrated considerable engagement with the assignment, averaging 14.5 posts to Wikipedia over a span of 50 days. Most connected Wikipedia editing with other course materials and reported benefits of peer-evaluating classmates' work. Most reported beneficial interactions with Wikipedians in the public domain, who flagged and/or reverted edits of dubious quality, while correcting errors. Students demonstrated improvements in information literacy and Wikipedia knowledge, with gains in locating and evaluating the quality of source materials.