While international human rights law enshrines family life as a cornerstone of society, when it intersects with migration, issues and problems arise in countries where migration is high on the political agenda. This is true in a number of EU states. Both EU law and European human rights commitments, however, require states to provide for family reunification subject to a margin of discretion to the state. While family reunification for refugees and beneficiaries of international protection has been at the top of some political agendas in Europe, this article looks at family reunification (generally known as family reunion) for another group—nationals of the Member States. In particular it poses two questions: do EU Member States accept their own nationals to come back to their home state with third country national family members they have acquired while abroad? Secondly, to what extent do EU Member States discriminate against their own nationals in comparison with the generous EU rules of family reunion for nationals of other Member States who have exercised a free movement right in their country. This article is based on reports by experts from all EU Member States in light of the 2014 judgment in O & B (C-456/12) by the Court of Justice of the European Union.