Zederik is a former municipality in the western Netherlands, in the province of South Holland. The municipality covered an area of 76.50 km² of which 2.77 km² is water. It had a population of in 2019.
The municipality of Zederik was formed on January 1, 1986, through the merger of the former municipalities of Ameide, Hei- en Boeicop, Leerbroek, Lexmond, Meerkerk, Nieuwland, and Tienhoven aan de Lek. Zederik merged with Leerdam and Vianen into the municipality of Vijfheerenlanden in the province of Utrecht on January 1, 2019. The municipality was named after the Old Zederik, a small canal running through its area.
The population centres of Zederik consisted of Ameide, Hei- en Boeicop, Leerbroek, Lexmond, Meerkerk, Nieuwland, and Tienhoven aan de Lek.