Christian democracy is a political ideology which emerged in nineteenth-century Europe under the influence of conservatism and Catholic social teaching. It was originally conceived as a combination of traditional Catholic beliefs and modern democratic ideas, but over time it grew to incorporate a variety of views from different Christian denominations and from different political thinkers. Christian democracy continues to be influential in Europe and Latin America, though throughout Europe the movement has been weakened by growing secularism.

Christian democratic parties are those political parties that seek to apply Christian principles to public policy. The underlying Christian democracy movement emerged in 19th-century Europe, largely under the influence of Catholic social teaching, and it continues to be influential in Europe and Latin America, though in a number of countries its Christian ethos has been diluted by secularisation. In practice, Christian democracy often advocates centre-right positions on cultural, social, and moral issues and Social market economic policies. In Europe, where their opponents have traditionally been secularist socialists, Christian democratic parties are moderately conservative overall, whereas in the very different cultural and political environment of Latin America they tend to lean to the left. It is the dominant political movement in Europe.