Otto Ackermann (14 February 1872, Berlin – 31 May 1953, Düsseldorf) was a 19th-century German painter, mainly of landscapes.
He was chairman of the local Düsseldorf Painters' Society and is mentioned in the diaries of Albert Herzfeld.
Ackerman travelled to Belgium, Italy and the Netherlands.
He mostly painted landscapes and Belgian and Dutch coastal and river scenes.
In the course of the Gleichschaltung of the Malkasten, which took place during the National Socialist era, Ackermann became the new chairman of the association in 1934 after a change in the bylaws.