Wilhelm Marx (15 January 1863 – 5 August 1946) was a German lawyer, Catholic politician and a member of the Centre Party.
He was Chancellor of Germany twice, from 1923 to 1925 and again from 1926 to 1928, and he also served briefly as Minister President of Prussia in 1925, during the Weimar Republic.
With a total of 3 years, 73 days, he was the longest-serving Chancellor during the Weimar Republic (when adding both of his terms; Heinrich Brüning had the longest continuous tenure with 2 years, 61 days, slightly longer than Marx' first term).