The Christian Union (Dutch: ChristenUnie [ˌkrɪstənˈyni, -təˈʔy-], CU) is a Christian democratic political party in the Netherlands. The CU is a centrist party, maintaining more progressive stances on economic, immigration and environmental issues while holding more socially conservative positions on issues, such as opposing abortion and euthanasia. The party describes itself as "social Christian".

The CU was founded in 2000 as a merger of the Reformed Political League (GPV) and Reformatory Political Federation (RPF). After doubling its seat tally in the 2006 Dutch general election, it became the smallest member of the fourth Balkenende cabinet, and since that time has been likewise part of the third Rutte cabinet and the fourth Rutte cabinet. In some elections it forms an alliance with the Calvinist Reformed Political Party (SGP), which, unlike the CU, is a testimonial party.

Primarily a Protestant party, the CU bases its policies on the Bible, and takes the theological principles of charity and stewardship as bases for its support for public expenditure and environmentalism. It seeks for government to uphold Christian morality, but supports freedom of religion under the doctrine of sphere sovereignty. The party is moderately Eurosceptic; it was formerly in the European Parliament with the European Conservatives and Reformists Group (ECR Group) and European People's Party Group (EPP Group). It is a member of the European Christian Political Party.

Along with the larger Anti-Revolutionary Party (ARP), the Netherlands has a long tradition of small orthodox or conservative Protestant (i.e., mostly Reformed) parties in parliament, including the Reformed Political Party (SGP), founded in 1918. After a group of Reformed Churches members formed the Reformed Churches (Liberated) over a religious disagreement, the Reformed Political Alliance (GPV) split off from the ARP in 1948. It took until 1963 for the party to enter parliament. In the 1981 election, the Reformatory Political Federation (RPF) entered parliament. It had split off from the ARP six years earlier over the formation of the Christian Democratic Appeal (CDA).

The RPF explicitly stated in its manifesto of principles that it sought to unite all reformed parties in the Netherlands.

The CU describes itself as a Christian social party. The party has its roots in orthodox Protestant (i.e. mostly Reformed) parties, often referred to as the "small right". It combines a conservative point of view on ethical and foreign policy issues, with more centre-left ideas on economic, asylum, social and environmental issues. Its conservative reformed ideals are reflected in its program of principles. It believes that the state is the swordmaiden of God. It bases its politics directly on the Bible. However, it sees separate duties for the state and the church in public life: the church should spread the Word of God, while the state should merely uphold public morality. The state should respect the religion of its citizens. Other Christian principles, such as neighbourly love and stewardship for the Earth, however have given the CU's political program a centre left orientation. The party has also been described as centre-left or left-wing overall.

Some of CU's socially conservative policies include:

More centre-left policies include: