Outside the United States (U.S.), very little is known about long-run trends in school productivity. We present new evidence using two data series from Australia, where comparable tests are available back to the 1960s. For young teenagers (aged 13-14), we find a small but statistically significant fall in numeracy over the period 1964- 2003, and in both literacy and numeracy over the period 1975-1998. The decline is in the order of one-tenth to one-fifth of a standard deviation. Adjusting this decline for changes in student demographics does not affect this conclusion; if anything, the decline appears to be more acute. The available evidence also suggests that any changes in student attitudes, school violence, and television viewing are unlikely to have had a major impact on test scores. Real per-child school expenditure increased substantially over this period, implying a fall in school productivity. Although we cannot account for all the phenomena that might have affected school productivity, we identify a number of plausible explanations.