Sava Kosanović (1894 - 1956) was Croatian and Yugoslav politician and diplomat, also known as the nephew of famous inventor Nikola Tesla.

He was born in Plaški as a son of Serbian Orthodox priest Nikola Kosanović and his wife Marica Tesla, sister of Nikola Tesla. He had three brothers and a sister.

He was educated in Rijeka gymnasium, and later studied law in Budapest. He started political career in 1918, during the collapse of Austria-Hungary, where in Plaški he helped set up administration of newly established State of Slovenes, Croats and Serbs, which soon became part of Yugoslav state.

He was enthusiastic supporter of Yugoslavism, but his views in new state evolved towards those of Svetozar Pribićević and his Independent Democratic Party which favoured federalisation and co-operation with Croatian Peasant Party. He soon became fierce opponent of King Alexander I and after start of 6 January Dictatorship he was put under house arrest. In 1930s he was one of the most outspoken antifascists among Yugoslav non-Communist politicians, which later brought him in conflict with pro-fascist prime minister Milan Stojadinović. He was also target of asassination attempt by Serbian fascists. In 1939, following Cvetković–Maček Agreement and creation of Banovina of Croatia, he became minister in government of Dragiša Cvetković.

His ardent antifascism brought him into conflict with Cvetković and other ministers during Yugoslav accession to the Tripartite Pact. He resigned his post in protest only to be brought into new government of Dušan Simović following March 27th 1941 coup d'état. During invasion of Yugoslavia he followed Simović's government into in exile. In 1942 he visited New York where he had met his famous uncle shortly before his death.

Kosanović soon began to clash with other ministers because he saw their policy as under influence of Greater Serbian nationalism. He gradually began to get close to the Communist-led Partisan movement. In January 1943 he was dismissed from the government and in December 1943 he began to publicly support Tito. Following Treaty of Vis he became minister of interiors in newly established government of Provisional Government of the Democratic Federal Yugoslavia. After the end of war and creation of Communist Yugoslavia he became its ambassador in Mexico and later in United States. At this post he worked very hard to bring as many of Tesla's documents and artifacts to Yugoslavia, and the result was creation of Nikola Tesla Museum in Belgrade.

Sava Kosanović appears as character in 1977 Yugoslav biographic TV series Nikola Tesla where he is played by Petar Božović.