Knud, Hereditary Prince of Denmark (Knud Christian Frederik Michael; 27 July 1900 – 14 June 1976), was the second son and younger child of Christian X and Alexandrine of Mecklenburg-Schwerin.

From 1947 to 1953, he was heir presumptive to his older brother, Frederick IX, and would have succeeded him as king had it not been for a change in the Danish Act of Succession that replaced him with his niece, Margrethe II.

Prince Knud was born on 27 July 1900 at Sorgenfri Palace in Kongens Lyngby north of Copenhagen during the reign of his great-grandfather, King Christian IX. His parents were Christian of Denmark, son of the heir apparent Frederick, and Alexandrine of Mecklenburg-Schwerin. Knud's only sibling, Frederick, had been born one year before him.

Christian IX died on 29 January 1906, and Knud's grandfather succeeded him as Frederick VIII. Six years later, on 14 May 1912, Frederick VIII died, and Knud's father ascended the throne as Christian X.

As was customary for princes at that time, Knud started a military education and entered the naval college. He married his first cousin, Princess Caroline-Mathilde of Denmark, on 8 September 1933 at Fredensborg Palace. She was a daughter of Frederick VIII's son Harald. Knud and Caroline-Mathilde had three children: Princess Elisabeth, Prince Ingolf and Prince Christian.

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