Otto Wels (b. 15 September 1873 in Berlin, Kingdom of Prussia, German Empire; d. 16 September 1939 in Paris, France) was a German politician who served as a member of parliament from 1920 to 1933 and as the chairman of the Social Democratic Party of Germany (SPD) from 1919 until 1933 when the party was banned.
In June 1933, Wels went into exile in the Territory of the Saar basin, which at the time was under League of Nations control. On 13 January 1935, the Saar region voted 90.3 % in favour of returning to Germany and he moved to Prague, where he established Sopade, the exiled organization of the SPD. As a result of the Munich Agreement, 30 September 1938, Wels decided to leave Prague and went to Paris.
Wels died on 16 September 1939 at the age of 66.
Since the 1980s with the Federal Republic of Germany he is hailed as a hero, although it is difficult to see what he did which was "heroic". Exactly 50 years after Wels speech in the Reichstag, on March 23, 1983, the council at Herten (in North Rhine-Westphalia, in the industrial Ruhr Area, some 5 km (3.1 mi) west of Recklinghausen) decided to name the central square in front of the town hall "Otto-Wels-Platz". An "Otto Wels" memorial plaque was installed later that year.