In economics, the Baumol effect, also known as Baumol's cost disease, is the rise of wages in jobs that have experienced little or no increase in labor productivity, in response to rising salaries in other jobs that have experienced higher productivity growth. The phenomenon was described by William J. Baumol and William G. Bowen in the 1960s and is an example of cross elasticity of demand.

The rise of wages in jobs without productivity gains derives from the requirement to compete for workers with jobs that have experienced productivity gains and so can naturally pay higher salaries, just as classical economics predicts. For instance, if the retail sector pays its managers low wages, they may decide to quit and get jobs in the automobile sector, where wages are higher because of higher labor productivity. Thus, retail managers' salaries increase not due to labor productivity increases in the retail sector, but due to productivity and corresponding wage increases in other industries.