Outside the United States, 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 1975–98. 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.