This chapter discusses one of the most basic putative cognitive kinds, concept, arguing that it should be considered a real kind based on our current state of knowledge, contrary to what some philosophers have urged. After surveying empirical work on concepts in cognitive neuroscience and cognitive psychology, the chapter tries to show that this work is pitched at different levels of explanation. Much recent work on concepts using neuroimaging techniques should not be expected to reveal the neural correlates of concepts because the research has different explananda and is investigating different causal processes. Other work on concepts in cognitive science reveals psychological structures (prototypes) associated mainly with automatic processing rather than deliberative reasoning. By contrast, concepts proper can be understood as functional kinds, which are individuated partly etiologically and partly with reference to the thinker’s discriminatory and inferential abilities. Many research programs in cognitive science individuate concepts in this way, combining diachronic and synchronic factors.