Spaso House is a listed Neoclassical Revival building at No. 10 Spasopeskovskaya Square in Moscow. It was originally built in 1913 as the mansion of the textile industrialist Nikolay Vtorov. Since 1933, it has been the residence of the U.S. ambassador to the Soviet Union, and since 1991, to the Russian Federation. The building belonged to the USSR and later Russia and, under the 1985 lease contract, the U.S. was supposed to pay 72,500 Soviet roubles per year, which by 2001 was the equivalent of about $3, which the U.S. had failed to pay in 1993. In 2004, the two sides concluded a new 49-year lease that was said to be based on a joint assessment of the property's value; the rent rate was not disclosed.

Spaso House takes its name from Spasopeskovskaya Square, in the Arbat District. "Spasopeskovskaya" meant "Saviour on the Sands", referring to the sandy soil of the neighborhood, which was first settled in the seventeenth century. Most of the original wooden houses on the square were burned by the fire of Moscow (1812). New stone houses were built soon afterwards, including two one-story mansions of plaster-covered stone with columned porticos, built by A. G. Shchepochkina, which stand today at number 6 and number 8 Spasopeskovskaya square, on either side of Spaso House.

In 1913 a large lot on the square was sold by Princess Lobanova-Rostovaya to the family of the Russian industrialist Nikolay Vtorov, who owned the largest textile manufacturing firm in Imperial Russia. Vtorov commissioned the architects Vladimir Adamovich and Vladimir Mayat, two prominent advocates of the neoclassical style, to build the new mansion. As a student, Adamovich had worked with F.O. Shekhel, the master of Russian Art Nouveau in the early 1900s. They chose the "New Empire" style, which was popular with the Russian business class. The exterior of the house was influenced by the Gagarin House, a fine example of the Muscovite Empire Style, which had been built in the 1820s by Joseph Bové.

Another likely source was the Polovtsev House in Saint Petersburg by Ivan Fomin, completed in 1913.

Externally and internally, Vtorov House was a recreation of an early 1820s upper-class estate, with palladian windows and a perfectly symmetrical floorplan. Work on the house began in April 1913, and by the summer the exterior was nearly completed. Work on the interior continued during the winter of 1913-1914. The house was completed and the Vtorovs moved in shortly before the beginning of World War I in August 1914.

In the turbulent months following the Bolshevik Revolution in 1917, Nikolay Vtorov died mysteriously and his family fled Russia. Spaso House was expropriated by the new Soviet government. Spaso House served as a reception house for the All-Russia Central Executive Committee, then as a residence for Soviet diplomats, including Georgi Chicherin, the People's Commissar for Foreign Affairs from 1918 to 1930, and Lev Karakhan, who was Chicherin's deputy.

After 16 years of not recognizing the Soviet Union, the United States finally established diplomatic relations with Moscow in 1933. The first American ambassador to the Soviet Union, William C. Bullitt (1891–1967), came to Moscow and selected a building on Mokhovaya street as the new U.S. Chancery and the Vtorov House as his temporary residence. The Vtorov House appealed to Bullitt because it had large space for entertaining and an American-style heating system, installed by the Soviet Government in 1928. The new third secretary of the embassy, George Kennan (1904–2005), negotiated a three-year lease for the property for $75,000. Bullitt did not ask for a longer lease, because he had a plan to build a new residence, similar to Thomas Jefferson's Monticello, in the Sparrow Hills, but the Soviet government never granted the land for the new house, so Spaso House became the permanent ambassador's residence.

Early in 1934, the ambassador and the first American diplomatic staff moved into Spaso House, which, due to structural problems with the Mohovaya street building, at first served as both the residence and embassy chancery. The U.S. government constructed a new ballroom for Spaso House in 1935 to provide more space for entertaining large groups. On July 4, 1934, Bullitt hosted the first Fourth of July reception at Spaso House, and also led a team of U.S. diplomats in a game of baseball against a team of Moscow-based American journalists.