Prince Frederick William of Solms-Braunfels (22 October 1770 in Braunfels – 13 April 1814 in Slawentzitz) was a Prussian Major General and by birth member of the House of Solms-Braunfels.

He was the fourth son of Ferdinand William Ernest, 2nd Prince of Solms-Braunfels (1721–1783) and his wife, Countess Sophie Christine Wilhelmine of Solms-Laubach (1741–1772).

Frederick William was alleged to have been strongly inclined to consume alcohol and had to quit military service in 1805 for health reasons.

He also lost his income and even his brother advised Frederica to divorce.

She was initially against it, but when in 1813, she met Ernest Augustus, King of Hanover (1771–1851), she, too, wanted the divorce.