凯尔派（Kelpie）是一种流传于凯尔特民间传说中的一种会变形的精灵，在苏格兰的传说中常以骏马的型态出现在湖边，诱拐或欺骗旅人。

对某些人而言，凯尔派与另一种极为相似的生物「水马」“each uisge”是不同的：凯尔派专指在淡水湖或河流的水妖精，在苏格兰当地的传说中，每座湖泊、河流都有守护它们的凯尔派，这些凯尔派会主动保护自己地域，因此每当有旅人接近，它就会化身为一只会唤惑旅人的少女或黑马、白马或俊男，当旅人骑上去后，就再也无法下来，然后凯尔派就会迅速跳至湖中，淹死不幸的旅人，以保护它守护的地方；而水马则只出没于咸水边，除了将人溺死外，还会吃掉受害者的身体，仅留下肝脏，比凯尔派更让人恐惧。

Kelpie, or water kelpie, is the Scots name given to a shape-shifting water spirit inhabiting the lochs and pools of Scotland. It has usually been described as appearing as a horse, but is able to adopt human form. Some accounts state that the kelpie retains its hooves when appearing as a human, leading to its association with the Christian idea of Satan as alluded to by Robert Burns in his 1786 poem "Address to the Deil".