Wikimedia Commons has media related to House of Windsor.

In 1917, during the First World War, King George V of the United Kingdom announced that he, and all other descendants of Queen Victoria in the male line, would change their surname from Saxe-Coburg-Gotha to Windsor. All such descendants may be included here.

Note that descendants of Queen Elizabeth II and their spouses are placed in a sub-category as they have the surname Mountbatten-Windsor.