The Holy See has been an OSCE participating State since June 25, 1973 and has a mission to the Organization in Vienna. (At the United Nations, the Holy See has voluntarily been a Permanent Observer to the United Nations, rather than a member State.) The Holy See represents the Catholic Church worldwide, including bilaterally – having full diplomatic relations with 180 countries – and in international fora. The Vatican City State is the smallest State in the world, with a population of 800 to 1,000 people and area of .17 square miles, and although a sovereign entity distinct from the Holy See, it is the physical base of the Holy See. The sovereignty of the Holy See extends globally to the entire Catholic Church.

The Holy See is recognized in international law as a non-territorial sovereign entity and is able to enter into treaties and other international agreements. At the OSCE, its priorities have included the peaceful resolution of conflicts, religious freedom, combating human trafficking, drug trafficking, and organized crime, disarmament and non-proliferation, refugees and migrants, protection of national minorities, combating terrorism, and the economy and environment and related implications for people.