The public administration literature asserts that autonomy is central to performance. In this article we develop a managerial autonomy index, which we apply to 22 water utilities in Africa, Asia and the Middle East. The 16 items that underlie our composite autonomy index display a high degree of internal consistency. This speaks for the validity of the autonomy concept. We find that the autonomy scores of the 22 utilities vary widely. We also find strong and positive associations between autonomy scores and six out of eight key performance indicators. Our results support the idea that autonomy is central to the performance of water service providers.