Jonas "Ivaška" Manvydas (Polish: Jan (Iwaszko) Moniwidowicz; died 1458) was a Lithuanian noble.
Manvydas was first recorded in written sources in May 1423 when he affixed his seal to the Treaty of Melno.
[1] In August 1431, he witnessed the truce of Chortoryisk that Grand Duke Švitrigaila concluded with the Teutonic Order (see Polish–Teutonic War (1431–1435)).
His uncle Jurgis Gedgaudas was captured in the Battle of Ashmyany and reconciled with the new Grand Duke Sigismund Kęstutaitis.
[1] In 1440, after the assassination of Sigismund Kęstutaitis, he supported Casimir Jagiellon against Michael Žygimantaitis and regained his influence in the Grand Duchy of Lithuania.