This is a list of Danish monarchs, that is, the kings and queen regnants of Denmark. This includes:

• The Kingdom of Denmark (up to 1397)
  • Personal union of Denmark and Norway (1380–1397)
• The Kalmar Union (1397–1536)
  • Union of Denmark, Norway and Sweden (1397–1523)
  • Union of Denmark and Norway (1523–1536/1537)
• The United Kingdoms of Denmark–Norway (1536/1537–1814)
• The Kingdom of Denmark (1814–present)
  • Iceland (since the union between Denmark and Norway in 1380; independent kingdom in a personal union with Denmark 1918–1944; a sovereign republic since 1944)
  • Greenland (since the union between Denmark and Norway in 1380; effective Danish–Norwegian control began in 1721; integrated into the Danish realm in 1953; internal home rule introduced 1979; self-rule assumed in 2009; Greenland has two out of 179 seats in the Danish parliament Folketinget)
  • Faroe Islands (since the union between Denmark and Norway in 1380; County of Denmark 1816–1948; internal home rule introduced 1948; The Faroe Islands have two out of 179 seats in the Danish parliament Folketinget)

The House of Oldenburg held the Danish Crown between 1448 and 1863, when it passed to the house of Schleswig-Holstein-Sonderburg-Glücksburg, a cadet branch of the same house, patrilineally descended from King Christian III of Denmark. The kingdom had been elective (although the eldest son or brother of the previous king was usually elected) until 1660, when it became hereditary and absolutist. Until 1864 Denmark was also united in a personal union with the duchies of Holstein and Saxe-Lauenburg (1815–1864), and in a political and personal union with the Duchy of Schleswig.

The exact date of origin of the Kingdom of Denmark is not established, but names of Danish kings begins to emerge in foreign sources from the 8th century and onwards. Danish and Nordic legendary stories, chronicles and sagas often have accounts of Danish kings and dynasties stretching further back in time than the 7th century, but the historicity of the content and interpretations of these stories are often put to doubt.

• Chochilaicus—see Hugleik and Hygelac—c. 515 AD, mentioned by Gregory of Tours (538–594).^[1][2][3] Hugleik, according to the written sources, suffered a defeat in 515 during a naval expedition to the Frankish Empire. Hugleik is the first Danish king mentioned in European sources.^[4]
• Ongendus (Angantyr): c. 710 Saint Willibrord wrote about when he visited the Danes, at the time ruled by Ongendus.^[5]
• Harald, named as former king in relating 9th-century events, perhaps model for legendary Harald Wartooth. Related to the Frisian king Redbad II who in 754 had to flee to "the land of the Danes" where King Harald reigned ("Daniae Regi Heraldi").^[6]
• Sigfred: 770s–790s
• Gudfred: 804–810, mentioned as Danish king in the Treaty of Heiligen 811.^[1] Alternate spellings: Godfred, Göttrick (German), Godric(Anglicized English), Gøtrik (Danish), Gudrød (Danish)
• Hemming: 810–811/812 The Treaty of Heiligen was signed in 811 between the Danish King Hemming and Charlemagne.^[1]
• Sigfred, nephew of Gudfred, and Anulo (Anlaufr), grandson or nephew of Harald, fought for the throne and both were killed, perhaps model for the legendary Sigurd Hring: c. 812
• Harald Klak and his brothers Ragnfrid and Hemming Halfdansson: 812–813 and again from 819/827. From 826 he and his household lived in exile with the Frankish emperor Louis the Pious, he was baptized by the bishop of Mainz in Ingelheim am Rhein. The last reference of Harald in the written sources are in the Annals of Fulda which records his execution for treason in 852.^[7]
• Sons of Gudfred (Godrik): 814–820s
  • Horik I: (814) 827–854, King of the Danes (at first ruling jointly with his unnamed brothers). The Frankish annals mention Horik on numerous occasions during the next couple of decades.^[5]
• Horik II: 854–860s. He is believed to have been the immediate successor of Horik I, but the annals are silent about the name of the Danish king for a few years after the disaster of 854. In 857, Horik II allowed Rorik to occupy the part of the kingdom between the sea and the Eider. Horik II was still alive in 864, when a letter was addressed to him by Pope Nicholas I.^[5]
• Late 9th century kings
  • Bagsecg: c. 860s–871
  • Halfdan: 871–877
  • Sigfred: c. 873–891. It is generally assumed that he was the immediate successor of Horik II, although that is not certain. His year of succession is unknown, but it was between 864 (when Horik II was still king) and his first appearance as king in the Frankish annals in 873. Sigifrid was baptized in 882.^[5]
  • Gudfred: 880s
  • Heiligo (Halga): 890s (?), described by Adam of Bremen as the immediate predecessor of the House of Olof.
• The "House of Olaf": late 9th century and early 10th century. This dynasty is described by Adam of Bremen, and members of this claimed dynasty are commemorated by the two Sigtrygg Runestones, which represent contemporary evidence that some of these kings controlled at least part of Denmark.^[8]
  • Olof, said by Adam to have come from Sweden and defeated Heiligo, taking the crown.
  • Gyrd and Gnupa, sons and joint successors of Olof, according to Adam. Gnupa is named by Widukind of Corvey as leader of the Danes in 934, and appears on the Sigtrygg Runestones.
  • Sigtrygg, son of Gnupa, memorialized on the Sigtrygg Runestones, presumably dating from shortly after 934.
• Eric the Victorious of Sweden mentioned by Adam of Bremen and Saxo Grammaticus as ruling Denmark after an invasion by Sweden together with Slavic warriors. Adam of Bremen got the information from Danish king Sweyn II. The Stone of Eric also describes an attack on Hedeby from the same period. Since Eric also, according to another source of Adam of Bremen, invaded the Holy Roman Empire. It virtually requires Eric to have been the king of Denmark. Therefore two independent sources describe Eric as the king of Denmark. ^{[9] [10]}

• Family tree of Danish monarchs
• Succession to the Danish throne
• List of Danish royal consorts
• Coronation of the Danish monarch
• Style of the Danish sovereign
• Danish Crown Regalia
• Danish Orders of Chivalry
• Lists of office-holders