恶魔的代言人（英语：devil's advocate），又称恶魔的辩护人、恶魔的辩护者、魔鬼的辩护者、魔鬼代言人，是指在辩论中针对多数派进行批判或反驳的人，亦或是指该职责。最早源自罗马天主教教会。

该种行为也被看作是辩论中的一种技巧。当一方使用压力要求另一方认可，导致批判和反驳难以进行时，会使得讨论无法正常进行，也往往会阻碍到全面的思考。为了避免这种情况，通常会设定拥有自由批判和反论权限的角色加以限制。

In common parlance, a devil's advocate is someone who, given a certain argument, takes a position they do not necessarily agree with (or simply an alternative position from the accepted norm), for the sake of debate or to explore the thought further. In taking this position, the individual taking on and playing the devil's advocate role seeks to engage others in an argumentative discussion process. The purpose of such a process is typically to test the quality of the original argument and identify weaknesses, if possible, in its structure, and to use such information to either improve or abandon the original, opposing position. It can also refer to someone who takes a stance that is seen as unpopular or unconventional, but is actually another way of arguing a much more conventional stance. The background of this word comes from an official position within the Catholic Church, in which a canon lawyer called the Advocatus Diaboli (Latin for "Devil's Advocate"), also known as the Promoter of Faith, "argued against the canonization (sainthood) of a candidate in order to uncover any character flaws or misrepresentation evidence favoring canonization."