During the Seljuk period, the first Oghuz clan to settle in the regior bore the name Yalvac, and this is the origin of the county's present name. The Anatolian Seljuks extended their military and politico control of the peninsula eventually establishing a sultanate baseci in Konya.
After the Mongol invasion in the first half of the 14th century, the Anatolian Seljuk realm broke up into a chaos of successor states-small localized Turkish principalities.
Yalvac fell within the borders of one of them, that of the Hamitoglu tribe. Under their tenure, Yalvac began to grow and recover its importance.The Devlethan (Ulu) mosque, built in the 14th century, is a work of the Hamitoglu period. This mosque, with its charming stonework and inscriptions set amidst fragrant roses, is a fine example of Turkish principalities-period architecture.In 1380, Ottomans took Yalvac under their rule. The architectural monuments built in this period reflect the importance given to art in the Ottoman Empire. Under the Republic, Yalvac was incorporated into the province of Isparta.