Uludağ [uˈɫudaː], the ancient Mysian Olympus, is a mountain in Bursa Province, Turkey, with an altitude of 2,543 m (8,343 ft). It is a popular center for winter sports such as skiing, and a national park of rich flora and fauna. Summer activities, such as trekking and camping, also are popular.

In Turkish, Uludağ means "Sublime Mountain", but in colloquial Turkish, the older name Keşiş Dağı, "Mountain of Monks," is still used. In ancient times the range of which it is a part, extending along the southern edge of Bithynia, was known as Olympos in Greek and Olympus in Latin, the western extremity being known as the Mysian Olympus and the eastern as the Bithynian Olympus, and the city of Bursa was known as Prusa ad Olympum from its position near the mountain. Throughout the Middle Ages, it contained hermitages and monasteries: "The rise of this monastic centre in the 8th c. and its prestige up to the 11th are linked to the resistance of numerous monks to the policy of the iconoclast emperors and then to a latent opposition to the urban, Constantinopolitan monasticism of the Studites.". One of the greatest monks of the Christian East, the wonder-working Byzantine monk Saint Joannicius the Great, lived as a hermit on this mountain.