Schloss Oldenburg (Oldenburg palace) is a schloss, or palace, in the city of Oldenburg in the present-day state of Lower Saxony, Germany. It is the former residence of the counts (1667–1785), dukes (1785–1815) and grand dukes (1815–1918) of Oldenburg.

The building now houses part of the State Museum for Art and Cultural History, especially its decorative arts and local history exhibitions, as well as some old master paintings. Immediately outside the palace to the west and north is the Schlossplatz. Opposite it, to the north, is the Schlosshöfe shopping mall, opened in 2011. To the south are the Prinzenpalais and Augusteum, also part of the State Museum for Art and Cultural History. To the southwest is the Elisabeth-Anna-Palais, adjacent to the Schlossgarten Oldenburg, the main public park in Oldenburg.

In 1607–1667, the present palace served as the residence of Anthony Günther, Count of Oldenburg (1583–1667). After his death without a legitimate heir, most of his land fell into the hands of the Danish royal family for more than a hundred years. During this period, a Danish governor resided in the castle.

In 1773, the Holstein-Gottorf family took over control of the newly created Duchy of Oldenburg until 1860. In that year, Grand Duke Nikolas Peter Friedrich (1827–1900) moved to the nearby Prinzenpalais.

By 1894, the palace was the residence of the hereditary Grand Duke Friedrich August (1852–1931). He abdicated as reigning Grand Duke during the November Revolution of 1918, and in 1919–20 the palace was transformed into the Landesmuseum Oldenburg by the Government of the State of Oldenburg. It was transferred to public ownership in 1923.