Yekaterina Gavrilovna Stravinsky (née Nosenko; January 25, 1881 – March 2, 1939) was a Russian and French painter and amanuensis who was the cousin and first wife of Igor Stravinsky.

Born in Gorval, a village in Minsk Governorate, she spent most of her childhood in Kiev, where her mother died from tuberculosis in 1883. Yekaterina contracted latent tuberculosis from her mother, which would manifest itself later in her adult life. By the end of the decade, she moved to Ustilug, where her father had purchased an estate that formerly belonged to the Lubomirski family. As she matured, she developed her talent for painting, calligraphy, and music. After her father's death in 1897, she and her sister inherited the estate. Between 1901 and 1905 she studied art at the Académie Colarossi in Paris.

She first met her cousin Igor in 1890 during his family's first visit to the Nosenko estate in Ustilug. Their relationship developed into a furtive romance—which was accepted, but not openly acknowledged by their families—that culminated with their marriage in 1906. After spending their honeymoon in Finland, the couple moved into Igor's family home in Saint Petersburg, where she gave birth to the first of their four children. They built a new summer cottage for their family in Ustilug, which they would visit every summer until the outbreak of World War I, and moved to their own apartment in Saint Petersburg in 1909. After his international success with The Firebird in 1910, they and their family continuously moved around Switzerland and France until 1934, when they settled into their final home together along the Rue du Faubourg Saint-Honoré in the 8th arrondissement of Paris. Throughout their marriage, Yekaterina was the first to whom Igor would play his newest music, which she enjoyed. She was the principal copyist of his scores, counseled him on private and professional matters, and was an important influence in his reembrace of Russian Orthodox Christianity.

Chronic disease and Igor's adulterous affair with Vera Sudeikina marked her later years. His confession resulted in what he later described as a "tearful, Dostoyevskian scene", but he and Yekaterina agreed to maintain the marriage and their family's unity. In what musicologist Stephen Walsh called "an atrocious act of self-immolation", she acquiesced to Igor's demands to serve as an intermediary between him and Vera, establish an amicable relationship with her, and deliver the regular financial stipend he provided for her. By the 1930s, Yekaterina's health degraded to the point where Robert Craft observed that her marriage "had almost become purely vicarious". Both she and her eldest daughter became fatally ill with pneumonia in late 1938. Yekaterina, who outlived her daughter by three months, died in 1939. She is buried at Sainte-Geneviève-des-Bois Russian Cemetery.

Yekaterina was born in the village of Gorval, located in the Rechitsky Uyezd of the Minsk Governorate, on January 25, 1881; and was christened on January 27. She was the second daughter of Gavriil Trofimovich, a college counselor and doctor who worked at Lukyanovskaya Prison, and Mariya Kirillovna Nosenko (née Kholodovsky); the couple was living temporarily at the Kholodovsky estate in Gorval at the time of Yekaterina's birth. Her father was a descendent of Cossacks who had served in the Chernigov Regiment; her mother descended from the Russian nobility, military officers, and government officials. Yekaterina's maternal aunt was Anna Kirillovna, later the wife of Fyodor Stravinsky and the mother of Igor. Mariya's first husband, whose ancestors included Ivan Pushchin, a Decembrist and friend of Alexander Pushkin, died from tuberculosis in 1876.

Yekaterina and her older sister Lyudmila spent most of their early childhood in Kiev. Although Gavriil had purchased property in Ustilug at some point in the early 1880s for the sake of moving his wife to a location where the weather would not aggravate her tuberculosis, there is no record of the Nosenko family living there until 1889. In October 1883, her mother died at the age of 35. A subsequent medical examination in June 1890 determined that Yekaterina had no trace of tuberculosis and that she was found to be "completely healthy", although in later life she became ill with the disease.

In 1887, Gavriil purchased an estate in Ustilug that consisted of several thousands of acres of land that had formerly belonged to the Lubomirski family. The Nosenko estate was soon recognized as one of the finest in the Volhynian Governorate and the family became known among locals for their charity work and efforts to improve social welfare. In the late 1890s, the Nosenkos built a free hospital, hired a doctor to attend to patients in the Ustilug area, and donated land for the establishment of a community cemetery. Later, when Yekaterina's sister married Grigory Belyankin, a graduate of the Marine Architecture Institute in Philadelphia, the family built a school and fire station as well. The Nosenko family was known for its benevolent treatment of their workers, who were among the few not to revolt against their owners during the Russian Revolution of 1905.

Gavriil died in 1897; he bequeathed the Ustilug estate to his daughters. His cousin Dmitri took over its management, while the responsibility for raising Yekaterina and her older sister Lyudmila was tasked to Sofiya Velsovskaya, a distant and elderly relative the Nosenko sisters nicknamed "Baba Sonya". Later, Grigory assumed control of the estate's daily affairs and modernized its equipment.