Twinning is an initiative of the European Commission that was launched in 1998 in the context of the preparation for enlargement of the European Union. It was conceived as an instrument for targeted administrative co-operation to assist Candidate Countries (CC) to strengthen their administrative and judicial capacity to implement Community legislation as future Member States (MS) of the European Union.

Twinning involves the beneficiary country (BC) selecting a Member State (MS) partner(s) which undertake(s) to transfer the requested hands-on public sector expertise available in its home administration. The contract between the 2 countries is called a Twinning Contract. There are two types of twinning contracts: standard twinning and twinning light. The same procedures generally apply to both types.

The standard twinning includes secondment of a full time Resident Twinning Adviser (a public sector official from the member state) for at least 12 months plus various other expert inputs, such as medium- and short-term specialists, training etc. 'Twinning Light' consists of the provision by a MS of well-defined public sector expertise, generally involving the delivery of short or medium term expertise by officials (civil servants).