Wilhelm Karl Grimm (24 February 1786 – 16 December 1859) was a German author, the younger of the Brothers Grimm.

He was born in Hanau, Germany and in 1803 he started studying law at the University of Marburg, one year after his brother Jacob started there.

In 1825 Wilhelm married Henriette Dorothea Wild, also known as Dortchen, at age 39. Together they had four childern: Jakob Grimm (3 April 1826–15 December 1826), Herman Friedrich Grimm (6 January 1828–16 June 1901), Rudolf Georg Grimm (31 march 1830–13 November 1889), and Auguste Luise Pauline Marie (21 August 1832–9 February 1919).

From 1837-1841, the Grimm Brothers joined five of their colleague professors at the University of Göttingen to form a group known as the Göttinger Sieben (The Göttingen Seven). They protested against Ernst August, King of Hanover, whom they accused of violating the constitution. All seven were fired by the king.

Wilhelm Grimm died in Berlin at the age of 73.