The main goal of this paper is to compare the relative technical efficiency of agriculture in Western Balkan countries to those of the European Union and to propose ways to improve the position of Western Balkan countries. The group of Western Balkan countries includes Serbia, Montenegro, North Macedonia, and Albania, which are candidate countries for European Union membership, as well as Bosnia and Herzegovina, which is currently a potential candidate. An input-oriented Data Envelopment Analysis model with the variable return to scale was applied to an 11-year period from 2006 to 2016. Input variables used in the model included labour, land, and capital, and the output was presented as the value of agricultural production. The highest average technical efficiency was achieved by the EU15 countries for the entire eleven-year period, while the Western Balkan countries had the lowest score. The source of this inefficiency was identified in lower levels of agricultural performance, e.g. a lower-level use of the primary production factors – labour and land.