The Reformed Churches in the Netherlands was the second largest Protestant church in the Netherlands and one of the two major Calvinist denominations along with the Dutch Reformed Church since 1892 until being merged into the Protestant Church in the Netherlands (PKN) in 2004. The PKN is the continuation of the Dutch Reformed Church, the Reformed Churches in the Netherlands and the Evangelical-Lutheran Church in the Kingdom of the Netherlands.

The Dutch Reformed Church was the largest Christian denomination in the Netherlands from the onset of the Protestant Reformation in the 16th century until 1930. It was the original denomination of the Dutch royal family and the foremost Protestant denomination until 2004. It was the larger of the two major Reformed denominations, after the Reformed Churches in the Netherlands was founded in 1892. It spread to the United States, South Africa, Indonesia, Sri Lanka, Brazil, and various other world regions through Dutch colonization. Allegiance to the Dutch Reformed Church was a common feature among Dutch immigrant communities around the world and became a crucial part of Afrikaner nationalism in South Africa.