This report presents the consensus outcome of an international panel of experts who reviewed the definition and classification of dystonia. Dystonia is defined as a movement disorder characterized by sustained or intermittent muscle contractions causing abnormal, often repetitive, movements, postures, or both. The movements are typically patterned, twisting, and may be tremulous. Dystonia is often initiated or worsened by voluntary action and associated with overflow muscle activation. The classification of dystonia is based on two axes: clinical characteristics (age at onset, body distribution, temporal pattern, coexistence of other movement disorders, and other neurological manifestations) and etiology (nervous system pathology and inheritance). The panel proposed a revised definition and classification scheme that addresses inconsistencies in previous terminology and aims to improve clinical utility and scientific research. The new classification aims to reduce ambiguity and facilitate communication between clinicians and researchers.This report presents the consensus outcome of an international panel of experts who reviewed the definition and classification of dystonia. Dystonia is defined as a movement disorder characterized by sustained or intermittent muscle contractions causing abnormal, often repetitive, movements, postures, or both. The movements are typically patterned, twisting, and may be tremulous. Dystonia is often initiated or worsened by voluntary action and associated with overflow muscle activation. The classification of dystonia is based on two axes: clinical characteristics (age at onset, body distribution, temporal pattern, coexistence of other movement disorders, and other neurological manifestations) and etiology (nervous system pathology and inheritance). The panel proposed a revised definition and classification scheme that addresses inconsistencies in previous terminology and aims to improve clinical utility and scientific research. The new classification aims to reduce ambiguity and facilitate communication between clinicians and researchers.