The objective of this paper is an efficiency analysis concerning higher education systems in European countries. Data have been extracted from OECD data-sets (Education at a Glance, several years), using a non-parametric technique--data envelopment analysis--to calculate efficiency scores. This paper represents the first attempt to conduct such an efficiency analysis at a system-level in a cross-country comparison, while focusing only on tertiary education. The role of the public sector has also been analysed, by looking at the percentage of public spending devoted to higher education, and the way the public funds are used (channelled through private subsidies or directly assigned to institutions). It has been found that there is a small core of efficient units (e.g. Switzerland, United Kingdom), and that the influence of the public sector seems to play a role in determining efficiency scores. Many elements, related to critical policies, have also been analysed adopting a semi-parametric approach, to better explain the performances and efficiency differentials. Some key-policy implications have been derived. (Contains 12 notes, 11 tables, and 2 figures.)