We present the results of a systematic literature review of research articles that selfidentify as describing the implementation of innovations from mathematics education research in educational practice. We classified 103 articles according to study type, the type of teaching/learning phenomenon the implementation targeted, and whether the innovation carrier was a curriculum reform, professional development, or a curriculum resource. We found that interest in implementation research increased from a modest number of published studies prior to 2003 to a peak in 2021. Other results highlight that projects that targeted teaching in line with the U.S. National Council of Teachers of Mathematics process standards were dominant when curricular reform acted as a carrier. Planning and design aspects of such projects were rarely reported, and projects were rarely discussed theoretically. Instead, such projects were commonly researched by studying teachers’ reform enactment. We discuss the consequences of this imbalance.