As of 2026-10-12, Council on Foreign Relations tops the list with 7,000 members.
- #1 Council on Foreign Relations — 7,000 members
American think tank on foreign policy
The Council on Foreign Relations (CFR) is an American think tank focused on U.S. foreign policy and international relations. Founded in 1921, it is an independent and nonpartisan 501(c)(3) nonprofit organization. CFR is based in New York City, with an additional office in Washington, D.C. Its membership has included senior politicians, secretaries of state, CIA directors, bankers, lawyers, professors, corporate directors, CEOs, and prominent media figures. Read more on Wikipedia.
Wikidata - #2 Chatham House — 3,968 members
international affairs think tank
The Royal Institute of International Affairs, also known as Chatham House, is a British think tank based in London, England. Its stated mission is "to help governments and societies build a sustainably secure, prosperous, and just world." It has been praised for providing a safe space for speakers and encouraging openness. Its current presidents are Theresa May, Valerie Amos, Baroness Amos and Helen Clark. Read more on Wikipedia.
Wikidata - #3 German Council on Foreign Relations — 3,180 members
Germany’s semi-official Council for Foreign Relations
The German Council on Foreign Relations is a prominent Germany foreign policy research institute. It is an independent, private, non-partisan and non-profit organisation, and actively takes part in policy formation and promoting the understanding of German foreign policy and international relations. It was established in 1955 in Bonn as a registered association, and relocated to Berlin in 1999. Read more on Wikipedia.
Wikidata - #4 Öko-Institut — 2,003 members
non-profit, private-sector environmental research institute in Freiburg, Baden-Württemberg, Germany (1977-)
The Öko-Institut is a non-profit, private-sector environmental research institute with its head office in Freiburg im Breisgau, Germany. Read more on Wikipedia.
Wikidata - #5 Deutsche Gesellschaft für Personalführung — 1,659 members
German think tank
source Wikidata - #6 Institut Solidarische Moderne — 861 members
German leftist think tank
source Wikidata - #7 Atlantik-Brücke — 826 members
political and economic think tank based in Germany
Atlantik-Brücke is a private non-profit association to promote German-American understanding and Atlanticism. Founded in Hamburg in 1952, it was located in Bonn between 1983 and 1999 and is now located in Berlin. Read more on Wikipedia.
Wikidata - #8 D64 – Zentrum für digitalen Fortschritt — 754 members
German digital political association
source Wikidata - #9 Green Budget Germany — 268 members
think tank in Germany
source Wikidata - #10 Friedrich Ebert Foundation — 130 members
German political foundation linked to the SDP
The Friedrich Ebert Foundation is a German political party foundation associated with, but independent from, the Social Democratic Party of Germany (SPD). Established in 1925 as the political legacy of Friedrich Ebert, Germany's first president, it is the largest and oldest of the German party-associated foundations. It is headquartered in Bonn and Berlin, and has offices and projects in over 100 countries. It is Germany's oldest organisation to promote democracy, political education, and... Read more on Wikipedia.
Wikidata