Neurofeedback or electroencephalographic (
EEG
) biofeedback is the practice of providing sensory feedback in an operant conditioning paradigm to modify or enhance the activity of the central nervous system including
EEG
, event‐related potentials, slow cortical potentials, and blood oxygenation level‐dependent signal of cortical or subcortical origin. The visualization of brain signals gives individuals the opportunity to gain awareness of their physiology and the information needed to learn self‐regulation or volitional control of specific brain activity for the purpose of symptom reduction or performance enhancement. A brief discussion of the origins of brain signal recording, development of classical and operant conditioning paradigms, and evolution of neurofeedback therapy is presented. The technical requirements and feedback presentation of
EEG
, quantitative
EEG
, slow cortical potentials, hemoencephalography, near‐infrared spectroscopy, and real‐time functional magnetic resonance imaging are discussed. An overview of the research investigating neurofeedback therapy as a treatment for psychiatric disorders is presented and includes outcome data related to attention‐deficit/hyperactivity disorder, generalized anxiety disorder, obsessive‐compulsive disorder, posttraumatic stress disorder, depression, dissociative disorder, learning disorders, schizophrenia, and substance abuse. The integration of neurofeedback into cognitive behavioral therapy protocols is discussed.