Treaty of Salynas (, ) was a peace treaty signed on 12 October 1398 by the Grand Duke of Lithuania Vytautas the Great and the Grand Master of the Teutonic Knights Konrad von Jungingen. It was signed on an islet of the Neman River, probably between Kulautuva and the mouth of the Nevėžis River. It was the third time, after the Treaty of Königsberg (1384) and Treaty of Lyck (1390), that Vytautas promised Samogitia to the Knights. The territory was important to the Knights as it physically separated the Teutonic Knights in Prussia from its branch in Livonia. It was the first time that the Knights and Vytautas attempted to enforce the cession of Samogitia. However, it did not solve the territorial disputes over Samogitia and they dragged on till the Treaty of Melno in 1422.