Middelplaathaven is a public harbour on the Grevelingenmeer, situated south of the Kabbelaarsbank near the western closing dike of the lake, in the Dutch province of Zeeland.

Originally built as a working harbour, it offers a number of berths in the southwestern part of the basin that provide good shelter even in the strong wind conditions typical of the area. The harbour is managed by the public authority De Grevelingen.

As is standard for its publicly operated moorings on the Grevelingenmeer, no provisioning services are available on site, and waste disposal facilities are limited. Dedicated jetties here accommodate vessels over 15 metres in length.

Those willing to make the short walk can find a broader range of supplies and amenities at the nearby marina on the Kabbelaarsbank.