Frederick VIII (3 June 1843 – 14 May 1912) was King of Denmark from 29 January 1906 until his death in 1912.

The eldest son of King Christian IX, nicknamed the Father-in-law of Europe, Frederick was related to royalty throughout Europe. He was heir apparent to the Danish throne and served as crown prince for more than 42 years. During the long reign of his father, he was largely excluded from influence and political power. Upon his father's death in 1906, he acceded to the throne at the advanced age of 62. In many ways, Frederick VIII was a liberal monarch who was much more favorable to the new parliamentary system introduced in 1901 than his father had been, being reform-minded and democratically inclined. Due to his late accession to the throne, however, Frederick's reign would last only six years, throughout which he was plagued by ill health.