Accreditation agencies, higher education institutions, and professional organizations all emphasize the importance of measuring and assessing the impacts or effects of teaching, learning, and other valued institutional activities. Academic libraries, one of the key players in providing and structuring instructional resources and services, also are expected to document how their performance contributes to institutional goals and outcomes. Using accreditation and ACRL sectional standards/criteria, higher education outcomes assessment research findings and recent findings from performance effectiveness studies, this article identifies important institutional outcomes to which academic libraries contribute; describes specific performance indicators whose measures of impacts and outputs provide evidence about progress and achievement; and offers a conceptual framework of assessment domains for the teaching–learning library.