Austrian Chancellors and Presidents: 1 chancellor
(chancellor) Otto Ender   1930-1931  
Austrian Dukes and Emperors: 1 duke, 1 emperor
Duke Otto the Merry   1330-1339  
Emperor Karl I (a.k.a. Otto)   1916-1918  
Bohemian Kings: 1 king
King Karel III (a.k.a. Otto)   1916-1918  
Danish Prime Ministers: 3 prime ministers
Tage Reedtz-Thott (a.k.a. Otto)   1894-1897  
Otto Liebe   1920  
Jens Otto Krag   1962-1968; 1971-1972  
Estonian Presidents and Prime Ministers: 1 prime minister, 1 prime minister/state elder
(prime minister/state elder) Otto Strandman   1919; 1929-1931  
(prime minister) Otto Tief   1944  
Fictional Characters from Television: 1 character
Otto Flick   1982   'Allo 'Allo!  
German Chancellors and Presidents: 1 chancellor
(chancellor) Otto von Bismarck   1871-1890  
German Kings and Holy Roman Emperors: 4 king-emperors
King-Emperor Otto I the Great   936-973  
King-Emperor Otto II the Red   961-983  
King-Emperor Otto III   983-1002  
King-Emperor Otto IV   1198-1215  
Hall-of-Famers: 1 football
(football) Otto Graham   1965  
Hungarian Kings and Queens: 2 kings
King Ottó III of Bavaria   1305-1308  
King Károly IV (a.k.a. Otto)   1916-1918  
Hungarian Presidents and Prime Ministers: 1 prime minister
Prime Minister Dénes Berinkey (a.k.a. Ottó)   1919  
Hurricanes and Tropical Storms: 2 hurricanes, 1 storm
Storm Otto   2004  
Hurricane Otto   2010  
Hurricane Otto   2016  
Nobel Prize Winners: 6 chemistry, 3 medicine, 1 physics
(chemistry) Otto Wallach   1910  
(medicine) Otto Fritz Meyerhof   1922  
(chemistry) Heinrich Otto Wieland   1927  
(chemistry) Adolf Windaus (a.k.a. Otto)   1928  
(medicine) Otto Heinrich Warburg   1931  
(medicine) Otto Loewi   1936  
(physics) Otto Stern   1943  
(chemistry) Otto Hahn   1944  
(chemistry) Otto Diels   1950  
(chemistry) Ernst Otto Fischer   1973  
Norwegian Prime Ministers: 2 prime ministers
Otto Blehr   1921-1923  
Otto B. Halvorsen   1920-1921; 1923  
Notable Artists: 4 painters, 1 architect, 1 fashion designer
Otto Wagner   1841-1918  
Georg von Rosen (a.k.a. Otto)   1843-1923  
Otto Hesselbom   1848-1913  
Otto Mueller   1874-1930  
Otto Dix   1891-1969  
Karl Lagerfeld (a.k.a. Otto)   1933-2019  
Notable Athletes: 1 football, 1 soccer
(football) Otto Graham   1921-2003  
(soccer) Otto Rehhagel   1938-  
Notable Evildoers: 1 persecutor
Adolf Eichmann (a.k.a. Otto)   1906-1962  
Notable Filmmakers: 1 director
Otto Preminger   1905-1986  
Notable Scientists and Inventors: 4 chemists, 2 physicists, 1 naturalist
Otto von Guericke   1602-1686  
Otto Friedrich Müller   1730-1784  
Otto Wallach   1847-1931  
Otto Diels   1876-1954  
Adolf Windaus (a.k.a. Otto)   1876-1959  
Otto Hahn   1879-1968  
Otto Stern   1888-1969  
Olympic Medalists: 4 bronze, 4 silver, 1 bronze/gold, 1 gold/silver, 1 silver/bronze
(silver) Otto Herschmann   1896   swimming - 100 m freestyle  
(silver/bronze) Otto Wahle   1900; 1904   swimming - 1500 m freestyle; swimming - 200 m obstacle; swimming - 400 m freestyle  
(bronze) Otto Nilsson   1908   javelin throw  
(silver) Otto Trieloff   1908   medley relay  
(bronze) Otto Scheff   1908   swimming - 400 m freestyle  
(silver) Otto Fahr   1912   swimming - 100 m backstroke  
(silver) Otto Neumann   1928   4x400 m relay  
(gold/silver) Otto Cordes   1928; 1932   water polo  
(bronze) Ruud van Feggelen (a.k.a. Otto)   1948   water polo  
(bronze) Herbert Schade (a.k.a. Otto)   1952   5000 m  
(bronze/gold) Ottó Boros   1956; 1960; 1964   water polo  
Other Royalty: 1 king, 1 prince consort
Otto of Greece   1832-1862   Greece  
Claus of the Netherlands (a.k.a. Otto)   1980-2002   Netherlands  
Saints: 2 blessed, 1 saint
Saint Otto of Bamberg   1060-1139  
Blessed Otto Neururer   1882-1940  
Blessed Karl of Austria (a.k.a. Otto)   1887-1922  
Swiss Presidents: 1 president
Otto Stich   1988; 1994  
Tolkien's Characters: 1 character
Otto Boffin   (m)