Waldensians, Waldenses, Vallenses or Vaudois are names for a Christian movement that startsin Lyon and spreads soon to the Cottian Alps in the late 1170s.The movement, named after founder Peter Waldo, advocates an adherence to the Gospel that leads to conflicts with the Roman Catholic Church.

By 1215, the Waldensians are declared heretical and subject to persecution.During the Protestant Reformation, Waldensian leaders join the Reformed church.

Thus the movement adopts many of the Calvinist tenets and becomes a Protestant denomination.Currently, active congregations remain in Europe, South America, and North America, most under the label of the Waldensian Evangelical Church.

Organizations, such as the American Waldensian Society, exist to maintain the history of this movement, with the declared goals of "proclaiming the Christian Gospel, serving the marginalized, promoting social justice, fostering inter-religious work, and advocating respect for religious diversity and freedom of conscience."