Ko Lan (Thai: เกาะล้าน, pronounced [kɔ̀ʔ láːn]) is one of the eastern seaboard islands of Thailand.

About four kilometres long and two kilometres wide occupying 3,411 rai,[1] Ko Lan is the largest of the "near islands" off south Pattaya, at the southeast end of the Bay of Bangkok, and on the east side of the Gulf of Siam.

Administratively Ko Lan belongs to the Amphoe Bang Lamung, Chonburi Province.

[1] The "Koh Larn Classic" is a sailing and running race event held at the nearby Royal Varuna Yacht Club in Pattaya.

Visitors and island residents generate about 50 tonnes of solid waste per day, mostly waste from food and plastic containers, foam and glass bottles, but Pattaya City authorities are only able to remove 20–25 tonnes per day.

The remaining daily 10 tonnes of refuse on Ko Lan is building up at a 12 rai sized dump site in the island's centre.