Since around 1930, the term “physicalism” has been used to designate an epistemic, semantic, and methodological (and anti-metaphysical) viewpoint associated with the Vienna Circle’s logical empiricism, as well as a metaphysical viewpoint, associated with contemporary analytical philosophy, according to which the world is in some manner exhaustively physical. In both cases, physicalism has involved a scientific approach to knowledge and reality and a commitment to physics occupying a special place among the sciences. In its metaphysical guise, physicalism is often centrally understood as a view about the place of mind in the natural world, according to which mental entities (thoughts, emotions, and experiences) are nothing over and above physical entities. This entry traces the use of “physicalism” to the present day and discusses issues and challenges facing contemporary metaphysical physicalism, along with philosophical projects inspired by the physicalist problematic.