New accountability instruments – performance indicators, audits, and financial incentives – are expected to replace traditional accountability instruments in NPM reforms. We test this expectation by looking at the accountability arrangements of semi-autonomous agencies as a typical example of NPM reforms. Our findings are based on survey data on 342 agencies in six countries. We identify four types of accountability arrangements in semi-autonomous agencies, in line with the four trajectories of public management reform identified by Pollitt and Bouckaert (2004). Accountability relations between agencies and ministries are determined by country-specific administrative regimes, types of agency, and to a lesser extent, agencies' policy fields. We identify new avenues for theory and research into the effects of reforms on accountability in the public sector, and on semi-autonomous agencies in particular.