Michał Kleofas Ogiński (25 September 1765 – 15 October 1833) was a Polish diplomat and politician, Grand Treasurer of Lithuania, and a senator of Tsar Alexander I. He was also a composer of early romantic music.
Ogiński was born in Guzów, Żyrardów County (near Warsaw) in the Kingdom of Poland. His father, Andrzej, was a Polish nobleman and governor of Troki, in the Grand Duchy of Lithuania. His mother, Paulina Szembek (1740–1797), was the daughter of Polish magnate, Marek Szembek, whose ancestors were Austrian, and Jadwiga Rudnicka, who was of Lithuanian descent. His first introduction to music arose during a visit to relatives at Słonim where Michał Kazimierz Ogiński had a contemporary European theatre that hosted opera and ballet productions. Michał Kleofas received an Enlightenment gentleman's education. He studied music with Osip Kozlovsky and took violin lessons from Giovanni Battista Viotti and Pierre Baillot.
Aged only 20, Ogiński was chosen as an envoy of the Polish–Lithuanian Commonwealth. He served as an adviser to King Stanisław August Poniatowski and supported him during the Great Sejm of 1788–1792. In 1790 he was despatched as a diplomatic representative to the United Kingdom, where he met with Lord Mansfield who warned him about the danger posed by the tri-partite powers about to dismember the Kingdom of Poland. After 1790, he was sent to The Hague as a diplomatic representative of Poland to the Netherlands and was Polish agent in Constantinople and Paris. In 1793, he was nominated to the office of Vice-Treasurer of Lithuania.