Twinning is an instrument for the cooperation between Public Administrations of EU Member States (MS) and of beneficiary countries. Beneficiaries include candidate countries and potential candidates to EU membership, as well as countries covered by the European Neighbourhood Policy.
More specifically, in the IPA region, Twinning aims to provide support for the transposition, implementation and enforcement of the EU legislation (the acquis).
It also strives to share good practices developed within the EU with beneficiary public administrations and to foster long-term relationships between administrations of existing and future EU countries.
Twinning projects are built around EU policy objectives agreed between the public authorities of the beneficiary country and the Member States. They include a broad variety of activities implemented by experts from Member States, leading to the achievement of mandatory results.
Two Project Leaders (one on behalf of the Member State leading the project, the other of the beneficiary administration) and a Resident Twinning Adviser (RTA) are the backbone of Twinning projects. The RTA coordinates the project and is seconded from the lead MS to the beneficiary administration for a minimum of 12 months. The work plan of a Twinning project usually foresees expert missions, training events and awareness raising visits.
More information here on the Twinning site of the European Commission.