Ananalysis has been made of the literature on friction and wear of polymer composites and nanocomposites prepared by compounding nanofillers with a polymer matrix. The most important group of triboengineering nanocomposites includes polymers containing carbon nanomaterials and nanosilicates. Nanofillers significantly affect the behavior of polymer macromolecules under friction, formation of transfer layers and wear debris, and finally the tribological performance of the composite. PEEK-based nanocomposites are becoming one of the most promising materials for applications in polymer-metal tribosystems. They were tested under dry friction against steel with standard conditions recommended by the International Organization for Standardization. The test data have confirmed the positive effect of combining nanofillers with conventional additives to a PEEK matrix.