A developmental relationship between a more experienced mentor and a less experienced partner referred to as a mentee or protégé. Usually - but not necessarily - the mentor/protégé pair will be of the same sex.

The roots of the practice are lost in antiquity. The word itself was inspired by the character of Mentor in Homer's Odyssey. Though the actual Mentor in the story is a somewhat ineffective old man, the goddess Athena takes on his appearance in order to guide young Telemachus in his time of difficulty.

Historically significant systems of mentorship include apprenticing under the medieval guild system, and the discipleship system practiced by both Rabbinical Judaism and the Christian church.