The Oosterschelde is an estuary in Zeeland, the Netherlands, between Schouwen-Duiveland and Tholen on the north and Noord-Beveland and Zuid-Beveland on the south.

Between Schouwen-Duiveland and Noord-Beveland there are two road connections, the Oosterscheldedam on the west and the Zeeland Bridge on the east.

The Oosterscheldedam, between Schouwen-Duiveland and Noord-Beveland, is the largest of 13 ambitious Delta works, designed to protect a large part of the Netherlands from flooding.

The nine-kilometer-long Oosterscheldedam was initially designed, and partly built, as a closed dam, but after public protest huge sluicegate-type doors were installed in the remaining four kilometers. These doors are normally open, but can be closed under adverse weather conditions. In this way the saltwater marinelife behind the dam is preserved and fishing can continue, while the land behind the dam is safe from the water.

It was the biggest, most difficult to build and the most expensive part of the Delta works. Work on the dam itself started in April of 1976 and was completed in June of 1986, though the road over the dam was completed only in November 1987. To facilitate the building an artificial island Neeltje-Jans was first created in the middle of the estuary.

Bus 133 of Connexxion passes the dam, see Zeeland.