Danish Estonia refers to the territories of present-day Estonia that are ruled by Denmark firstly during the 13th–14th centuries and again in the 16th–17th centuries.Denmark had risen as a great military and mercantile power in the 12th century.

It has an interest to end the frequent Estonian Viking attacks that threatened its Baltic trade.

Danish fleets had attacked Estonia in 1170, 1194, and 1197.

In 1206, King Valdemar II and archbishop Andreas Sunonis led a raid on Ösel island (Saaremaa).

The Kings of Denmark lay a claim on Estonia as their possession, which is recognized by the pope.

In 1219, the Danish fleet lands in the major harbor of Estonia and defeats the Estonians in the Battle of Lyndanisse, which bringsNorthern Estonia under Danish reign until the Estonian uprising in 1343, when the territories are taken over by the Teutonic Order and sold by Denmark in 1346.In 1559, during the Livonian war, the Bishop of Ösel-Wiek in Old Livonia sells his lands to King Frederick II of Denmark for 30,000 thalers.

The Danish king gives the territory to his younger brother Magnus who lands on Saaremaa with an army in 1560.

The whole of Saaremaa becomes a Danish possession in 1573, and remains so until it is transferred to Sweden in 1645.