Ewald Georg von Kleist (10 June 1700 – 11 December 1748) was a German jurist, Lutheran cleric, and physicist.
A member of the von Kleist family, Ewald was born in Vietzow (Wicewo) in Farther Pomerania. He studied jurisprudence at the University of Leipzig and the University of Leyden and may have started his interest in electricity at the latter university under the influence of Willem 's Gravesande. From 1722-1745 he was dean of the cathedral at Kammin in the Kingdom of Prussia, after which he became president of the royal court of justice in Köslin.
On 11 October 1745 he independently invented the Kleistian jar which could store electricity in large quantities. He communicated this discovery to a group of Berlin scientists in late 1745, and the news was transferred in a confused form to Leyden University where it was further investigated. This became more commonly known as the Leyden jar after 's Gravesande's graduate student Pieter van Musschenbroek of Leyden.