Conrad Ulrich Sigmund Wille (5 April 1848 – 31 January 1925) was a Swiss military officer who served as General of the Swiss Army during the First World War. Inspired by the Prussian techniques that he had been able to observe at the time of his studies in Berlin, he attempted to impress the Swiss Army with a spirit based on instruction, discipline and technical control.

Wille was born on 5 April 1848 in Hamburg, Germany to journalist François Wille [de] (1811–1896) and novelist Eliza Wille [de] (née Sloman, 1809–1893). The Wille family was originally from La Sagne in Neuchâtel, a French-speaking Swiss canton. One of his ancestors, Henri Vuille (1714–1760), moved to Germany and altered the family name to the more German "Wille". François Wille, a radical democrat, was elected to the Frankfurt National Assembly during the German revolutions of 1848–1849. Wille's family left Hamburg after the revolution's failure, settling in Switzerland in 1851.

Wille grew up in Mariafeld, the family estate in Meilen in the canton of Zürich. He attended a cadet school alongside primary school, and was then educated by his parents. From 1865, Wille studied law at Zürich, Halle, and Heidelberg, where he obtained a doctorate in 1869.

During the Franco-Prussian War, Wille, then a lieutenant, was posted to the borders as part of the Swiss mobilization of 1870-1871. Under Hermann Bleuler's influence, he began a career as an artillery instructor in 1871. Wille was sent to the 1st Artillery Regiment of Prussia's Guard Corps and to the United Artillery and Engineering School in Berlin. He completed his education at Switzerland's Federal Instructor School in 1872, and two years later was appointed captain in the federal artillery staff.

From the beginning of his activity as an instructor in Thun in 1872, Wille reflected on the methods to be applied in his field and published articles on military policy. In 1880 he bought the Zeitschrift für Artillerie und Genie ("Journal for Artillery and Engineering"), which he used to campaign for military training reform according to the Prussian model until his appointment as chief instructor of the cavalry. Promoted to colonel in 1885, Wille was made commander of the cavalry in 1892.

Upon the outbreak of the First World War, Switzerland confirmed its will to remain neutral and issued a general mobilization of all military forces. On 3 August 1914, Wille was elected General by the United Federal Assembly with 122 votes, against 63 votes for Theophil Sprecher von Bernegg. Sprecher would soon assume the post of Chief of the General Staff and become a reliable partner of Wille's.

During the First World War, Switzerland was divided between the German-speaking Swiss, who tended to favor the Central Powers, and the French and Italian-speaking Swiss, whose opinions tended to support the Allies. As a Germanophile, close to Kaiser Wilhelm II, Wille benefitted from the pro-German current and the disparity within the Swiss Federal Council, which counted only one member from the French areas. The opponents of the general described him as militarist, whereas his partisans saw in him a leader ready to manage an army in mobilization thanks to his pedagogical talents. Wille decided to concentrate the bulk of his forces (238,000 men and 50,000 horses) close to the borders, particularly in Ajoie and Engadin.

The mandate of Wille was rife with political problems. A scandal occurred in the French-speaking area of Switzerland when Wille proposed to the Federal Council on 20 July 1915, to enter the war on the side of the Central Powers. Thereafter, the "Colonels' Affair" in 1916 also had a great repercussion. Two Swiss colonels had given German and Austro-Hungarian diplomats specimens of the "Staff Gazette", a confidential journal, and Russian messages deciphered by Swiss cryptanalysts. The affair risked Swiss neutrality since it implied collusion with one of the belligerents. Wille decided to condemn the two colonels to 20 days' detention, an unsatisfactory sentence in the eyes of the pro-Allied party.