Eliminative materialism (also called eliminativism) is a materialist position in the philosophy of mind. It is the idea that the majority of mental states in folk psychology do not exist. Some supporters of eliminativism argue that no coherent neural basis will be found for many everyday psychological concepts such as belief or desire, since they are poorly defined. The argument is that psychological concepts of behaviour and experience should be judged by how well they reduce to the biological level. Other versions entail the non-existence of conscious mental states such as pain and visual perceptions.

Eliminativism about a class of entities is the view that the class of entities does not exist. For example, materialism tends to be eliminativist about the soul; modern chemists are eliminativist about phlogiston; and modern physicists are eliminativist about the existence of luminiferous aether. Eliminative materialism is the relatively new (1960s–1970s) idea that certain classes of mental entities that common sense takes for granted, such as beliefs, desires, and the subjective sensation of pain, do not exist. The most common versions are eliminativism about propositional attitudes, as expressed by Paul and Patricia Churchland, and eliminativism about qualia (subjective interpretations about particular instances of subjective experience), as expressed by Daniel Dennett, Georges Rey, and Jacy Reese Anthis. These philosophers often appeal to an introspection illusion.

In the context of materialist understandings of psychology, eliminativism is the opposite of reductive materialism, arguing that mental states as conventionally understood do exist, and directly correspond to the physical state of the nervous system. An intermediate position is revisionary materialism, often argues the mental state in question will prove to be somewhat reducible to physical phenomena—with some changes needed to the common sense concept.

Since eliminative materialism arguably claims that future research will fail to find a neuronal basis for various mental phenomena, it may need to wait for science to progress further. One might question the position on these grounds, but other philosophers like Churchland argue that eliminativism is often necessary in order to open the minds of thinkers to new evidence and better explanations. Views closely related to eliminativism include illusionism and quietism.