Flentrop Orgelbau, based in Zaandam, Netherlands, with workshops for metal and wood processing in Koog aan de Zaan, has been a prominent organ-building company since its establishment in 1903. The company has built over 400 organs and exported many instruments globally. Besides constructing new organs, Flentrop Orgelbau is renowned for its restoration work. A notable project was the reconstruction of the organ at Hamburg's main church, Sankt Katharinen, completed in 2013.

The company was founded by Hendrik Wicher Flentrop (1866–1950), an organist in Zaandam who also started a piano and organ business. He was a pioneer in historically oriented organ building, aiming to restore organs to their original states rather than altering them to contemporary tastes. Influenced by the Organ Reform Movement, he and his son Dirk Andries Flentrop, who took over the business in 1940, preferred mechanical action and slider chests. Under Dirk's leadership, significant restorations were undertaken, including those of the Laurenskerk organs in Alkmaar, the Schnitger organ in Zwolle, and the historic organ of Mexico City's cathedral.

From 1976 to 1998, Johannes Antonij Steketee led the company, securing international projects such as the large organ for Holy Name Cathedral in Chicago. His successor, Cees van Oostenbrugge, continued until 2008. Frits Elshout then took over, with Erik Winkel assuming overall leadership in 2016. The company remains a key player in both new organ construction and the meticulous restoration of historic instruments.

https://de.wikipedia.org/wiki/Flentrop_Orgelbouw