"FC Barcelona won the CLUB WORLD RANKINGS of the first Decade (2001-2010) and also of the second Decade (2011-2020)," the IFFHS said in a statement.
Barca topped the list 2,877 points, while rival Real Madrid and Bayern Munich ranked 2nd and 3rd with 2,782 and 2,594 points, respectively.
Turkey's Fenerbahce stood at 65 with 1,310 points, Besiktas took 79th place with 1,229, while the 111th-placed Galatasaray received 1,104 points.
Founded in 1899, FC Barcelona have won five UEFA Champions League titles, three FIFA Club World Cups, five UEFA Super Cup trophies and 26 Spanish La Liga tournaments.
The IFFHS chronicles history and records of association football. It was founded in 1984 in Leipzig, Germany and is today registered in Zurich, Switzerland.