Midden-Delfland (Dutch: [ˌmɪdə(n)ˈdɛl(ə)flɑnt] ⓘ) is a municipality (gemeente) in the Westland region in the province of South Holland in the Netherlands.

It had a population of 19,414 in 2021, and covers an area of 49.38 km2 (19.07 sq mi) of which 2.19 km2 (0.85 sq mi) is water.

Dutch topographic map of the municipality of Midden-Delfland, June 2015 The green area that comprises the municipality of Midden-Delfland was named Midden-Delfland before 2004, and it referred to the green area surrounded by cities (such as The Hague and Rotterdam) and the horticulture area of Westland.

The supporters of a continuous green area were lucky that the municipality of Midden-Delfland became a reality: the cities of Delft, Vlaardingen and Schiedam wanted to build new houses here, and the Westland gardeners also wanted to expand.

Now, Midden-Delfland is designated as a recreation area for people from the surrounding cities.