Harku manor (Estonian: Harku mõis, German: Hark) was a manor in Harjumaa, Estonia. According to current administrative borders it is located on Harku Parish in Harju County.
Building was first built as a small stronghold and only later became manor. In the Middle Ages the manor served as a residency for the centre of vice commandment of Tallinn. In 1679 the manor was acquired by the famous family of von Uexküll and by the 18th century they had started constructing the Baroque-styled main building.
In September 1710 the half-finished Harku Manor was used as a place to sign the capitulation contract between Russian forces and Sweden with local nobility. The contract ended The Great Northern War and became the main foundation for the 18–19th century Baltic Special Agreements by which Estonia, going under the Russian reign for 200 years, retained its considerable autonomy and did not become a typical Russian province.
The von Budbergs, that acquired the manor in 1755, rebuilt the building into Early Classicism style. The Neo-Renaissance style look the manor has now was given by von Ungern-Sternbergs in 1875. The building was also made longer.
From 1892 the manor had many different owners and was bought by Hermann von Harpe in 1912 for 300 000 rubles. The same year von Harpe sold some of the property to 158 peasants. In 1919 the manor was expropriated from Hermann von Harpe.
In the 1920–1930s, right before the World War II, the building served many roles: rehabilitation facility for under aged criminals (so-called “Harku kolonn”); Harku prison for adults; Harku Work Camp for Work Despisers for drunks and work avoiders. Prisoners had to work in peat bogs and on manor fields. Working with livestock and crops provided extra food. Peat industry turned out to be especially beneficial because the government needed a lot of peat for heating. 1924 was the year of prisoners strike in Harku prison.
From 1957 Harku Manor housed the Institute of Experimental Biology and was owned by Estonian Academy of Sciences and later Estonian University of Life Sciences.
Since 2014 Harku Manor is owned by Baula Arendus OÜ.