Kukup Island () is an island in Pontian District, Johor, Malaysia.
The island is predominantly covered by mangrove and mudflat. It is surrounded by 8 km<sup>2</sup> of mudflat. Recently (2018) it was rumored that the island holds large deposits of gold.
The island is located around 1 km offshore from Johor mainland. The island spans over an area of 4.88 km<sup>2</sup>.
The island consists of various wildlife animals, such as monkeys, wild boars, mudskippers etc.
Kukup Island status as a remote hinterland changed in the 1990s when scientists began focusing on the island's biodiversity a unique ecological characteristics. In the interest of preserving this unique habitat, Kukup Island was gazetted a national park on 27 March 1997 under the Johor State Park Corporation Enactment 1989. On 31 January 2003, this island was granted the status of a "Wetland of International Importance", or Ramsar site, by the Geneva-based Ramsar Convention Bureau.