In an empirical investigation, the paper identifies the main political economy drivers of structural policy changes in OECD countries' labour and product markets over the 1985-2003 and 1973-2003 periods respectively. Some of the drivers are beyond the control of governments (i.e., that are exogenous to the political process) while there are others over which governments may have some leverage. The core empirical results, based on a set of policy indicators that cover 21 countries, suggest that the former set of factors has an important influence on the implementation of structural reform, including economic crises, exposure to foreign competition, and government?s duration in office. Nonetheless, the latter set of factors, including budgetary conditions and spillovers across policy areas -- in particular from the product to the labour market -- is also important to both initiate and sustain reforms.