The study summarized in this policy brief analyzed available data on the financing of teacher professional development in this country. It drew from data gathered in 1992, 1995, and 1998 by two national surveys of public school districts. Overall, expenditures for instructional staff support grew slightly during the 1990s. As a share of total budgets, it increased by one quarter of one percent. However, 23 states reported an increase less than this, and 17 states actually reported a decrease. A few--the District of Columbia, New Mexico, Kansas, Louisiana, and Wisconsin--increased their expenditures at twice the national average between 1991-92 and 1997-98. Several states decreased their expenditures quite significantly (Kentucky, Hawaii, Oregon, New Jersey, and North Carolina). The per-pupil expenditure increased from $168 to $241, or a 43% increase, but inflation makes this a nominal change. Furthermore, the spending variability within states generally remained stable although some, notably Texas, experienced a dramatic reduction in the variability of spending among its districts. Implications for research and policy are discussed. (Contains 2 tables.) [This Center for the Study of Teaching and Policy (CTP) Brief is based on an article published in The Journal of Education Finance, "School District Spending on Professional Development: Insights Available from National Data (1992-1998)," Summer 2002 (Kieran M. Killeen, David H. Monk, and Margaret L. Plecki).]