A growing number of countries in the OECD and beyond are moving toward asymmetric decentralisation, i.e. a differentiated assignment of competencies across subnational governments, for the same level of administration. While from the 1950s to the 1970s, asymmetric arrangements happened mostly at a regional level, the present trend seems to apply asymmetric decentralisation mostly in case of urban areas. Such trends may be further reinforced by the current global COVID-19 crisis, which has had highly asymmetric impact within countries. This paper aims to shed light on the various forms of asymmetric decentralisation. The study examines arguments from both economic research and policy practice angles. The paper highlights the pitfalls to avoid and good practices when implementing asymmetric decentralisation policies to reap their benefits and to minimise their costs.