This paper identifies existing and potential measures of teacher qualifications as a single aspect of teacher quality, emphasizing their underlying rationale, ways to use them, and availability and quality of data collected from various sources. It categorizes types of teacher qualification measures, discusses data sources, and notes availability and quality of data collected from these sources. The paper groups measures of teacher qualifications into four categories: ability or aptitude, content knowledge, pedagogic knowledge, and teaching credentials. The two principal data sources are self-reports on questionnaires like the Schools and Staffing Survey (SASS) and teachers' academic and test-score records maintained by colleges/universities, the Educational Testing Service, and the American College Testing Company. The review suggests that most data collected on teacher qualifications are general information with response rates similar to other non-sensitive items. Collecting highly specific, sensitive, or difficult to recall information has been done less often, with response rates substantially lower than average. The SASS and the Baccalaureate and Beyond study collect the most information on the broadest range of teacher qualification measures. Teachers' academic records provide the most complete picture of teacher qualifications, but access to these records has legal and financial considerations. An appendix presents tables showing teacher qualification measures, data collection surveys, and sources. (Contains 15 references.) (SM)