Oy or OY may refer to:
The Oyster card is a form of electronic ticket used on public transport in Greater London in the United Kingdom.
Oymyakon (Russian: Оймяко́н, pronounced [ɐjmʲɪˈkon]; Yakut: Өймөкөөн, Öymököön, IPA: [øjmøˈkøːn]) is a rural locality (a selo) in Oymyakonsky District of the Sakha Republic, Russia, located along the Indigirka River, 30 kilometers (19 mi) northwest of Tomtor on the Kolyma Highway.
The Oyster Bay History Walk is a path through downtown Oyster Bay, New York that leads the walker to 30 historic sites.
The Oyu Tolgoi mine (Mongolian: Оюу Толгой, also Oyu Tolgoi, Turquoise Hill) is a combined open pit and underground mining project in Khanbogd sum within the south Gobi Desert, approximately 235 kilometres (146 mi) east of the Ömnögovi Province capital Dalanzadgad.