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.

It was formed on 1 January 2004 through the merger of the former municipalities:

The municipality comprises the population centres:

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.