The formation of a vast number of different multi-element active sites in compositionally complex solid solution materials, often more gene­rally termed high-entropy alloys, offers new and unique concepts in catalyst design, which are mitigating existing limitations and change the view on structure-activity relations. We discuss these concepts by summarising the presently existing fundamental knowledge and criti­cally assess the chances and limitations of this material class also highlighting design strategies. A roadmap is proposed, illustrating which of the characteristic concepts could be exploited using which strategy, and which breakthroughs might be possible to guide future research in this highly promising material class for (electro)catalysis.