The Library and Information Research Group (LIRG) and the Society of College, National, and University Libraries (SCONUL) are working together on a joint initiative looking at the impact of higher education libraries on learning, teaching, and research. Twenty-two libraries have been involved in assessing the impact of particular services or new innovations in their institutions. This article considers why measuring impact is important, describes the background to the Impact Initiative and what led to it being set up, identifies the institutions that are involved and their chosen topics, outlines what is involved for the participating institutions, and reviews progress to date