Article 21 (2. c) of the Lisbon Treaty states that "the Union shall define and pursue common policies and actions, and shall work for a high degree of cooperation in all fields of international relations, in order to preserve peace, prevent conflicts and strengthen international security, in accordance with the purposes and principles of the United Nations Charter, with the principles of the Helsinki Final Act and with the aims of the Charter of Paris, including those relating to external borders."

The EU and the OSCE share a strong interest in co-operating on security-related discussions and conflict prevention in Europe and co-operate closely at all levels, including in the field. The EU and the OSCE pursue a permanent political dialogue among their members and co-ordinate efforts in pursuing common objectives and finding shared solutions. The agendas of the two organisations overlap to a considerable degree.

In 2018, the EU and the OSCE exchanged letters, at the level of Secretary General, agreeing to strategically strengthen their institutional interaction, as well as their operational co-operation in areas of common interest across the three dimensions.

All EU Member States are participating States of the OSCE. EU Member States contribute more than two-thirds of the OSCE's main budget and the EU and EU Member States also contribute to the funding of a number of OSCE implemented extra-budgetary projects. Examples of EU support for the OSCE include assistance to ODIHR in developing national electoral and human rights institutions and crisis management, for instance in the Western Balkans.

The EU Delegation to the International Organisations in Vienna co-ordinates the EU policies in the OSCE on a day-to-day basis and represents the EU in the OSCE.