Functional Neurological Disorder (FND), formerly known as conversion disorder, is a condition characterized by neurological symptoms without identifiable organic causes. These symptoms, which can include motor, sensory, or cognitive disturbances, are not deliberately produced and often vary in severity. Diagnosis is based on clinical evaluation and the exclusion of other medical or psychiatric conditions. Treatment typically involves a multidisciplinary approach, combining medical management, psychotherapy, and supportive interventions. Recent advances in neuroimaging and a deeper exploration of its epidemiology, pathophysiology, and clinical presentation have provided new insights into FND. This review highlights the phenotypic heterogeneity of FND, the diagnostic challenges it presents, and the significant role of neuroimaging in understanding its complex neural underpinnings. It also discusses the potential of neuroimaging in predicting treatment response and the importance of nuanced understanding in clinical practice and future research. FND is associated with various biological, psychological, and social factors. Neurobiological factors include abnormalities in neurotransmitters, inflammatory markers, and neuroplasticity. Psychological factors such as stressful life events, interpersonal conflicts, and adverse childhood experiences play a crucial role. Environmental factors, including cultural attitudes and social support networks, also contribute to FND's pathophysiology. Recent studies have revealed varying rates of prevalence and incidence for FND across different populations, with higher rates in industrialized nations. FND is estimated to comprise at least 5% to 10% of new neurological consultations and affects approximately 12 cases per 100,000 people per year in the UK. The disorder is often associated with pre-existing psychiatric disorders, other somatic conditions, and functional somatic disorders. Neuroimaging studies have shown altered activity in limbic and salience networks, disruptions in self-agency and multimodal integration, and alterations in attentional and sensorimotor circuits in FND patients. These findings suggest a multi-network brain disorder involving limbic, salience, self-agency, multimodal integration, attentional, and sensorimotor circuits. The diagnosis of FND relies on clinical evaluation and the exclusion of other conditions. Neuroimaging techniques have been instrumental in identifying alterations in brain networks, providing a biological basis for the disorder. However, the interpretation of neuroimaging findings must consider the phenotypic heterogeneity of FND, including varying symptom severity, episodic vs. persistent symptoms, and symptom overlap. Neuroimaging has emerged as a key tool in elucidating the pathophysiological underpinnings of FND, with preliminary data suggesting predictive value in determining treatment response. Personalized treatment strategies based on neuroimaging findings face challenges, including the complexity of interpreting imaging data and the need for specialized skills. Future research efforts are essential to deepen the understanding of FND and develop targeted, effective treatments.Functional Neurological Disorder (FND), formerly known as conversion disorder, is a condition characterized by neurological symptoms without identifiable organic causes. These symptoms, which can include motor, sensory, or cognitive disturbances, are not deliberately produced and often vary in severity. Diagnosis is based on clinical evaluation and the exclusion of other medical or psychiatric conditions. Treatment typically involves a multidisciplinary approach, combining medical management, psychotherapy, and supportive interventions. Recent advances in neuroimaging and a deeper exploration of its epidemiology, pathophysiology, and clinical presentation have provided new insights into FND. This review highlights the phenotypic heterogeneity of FND, the diagnostic challenges it presents, and the significant role of neuroimaging in understanding its complex neural underpinnings. It also discusses the potential of neuroimaging in predicting treatment response and the importance of nuanced understanding in clinical practice and future research. FND is associated with various biological, psychological, and social factors. Neurobiological factors include abnormalities in neurotransmitters, inflammatory markers, and neuroplasticity. Psychological factors such as stressful life events, interpersonal conflicts, and adverse childhood experiences play a crucial role. Environmental factors, including cultural attitudes and social support networks, also contribute to FND's pathophysiology. Recent studies have revealed varying rates of prevalence and incidence for FND across different populations, with higher rates in industrialized nations. FND is estimated to comprise at least 5% to 10% of new neurological consultations and affects approximately 12 cases per 100,000 people per year in the UK. The disorder is often associated with pre-existing psychiatric disorders, other somatic conditions, and functional somatic disorders. Neuroimaging studies have shown altered activity in limbic and salience networks, disruptions in self-agency and multimodal integration, and alterations in attentional and sensorimotor circuits in FND patients. These findings suggest a multi-network brain disorder involving limbic, salience, self-agency, multimodal integration, attentional, and sensorimotor circuits. The diagnosis of FND relies on clinical evaluation and the exclusion of other conditions. Neuroimaging techniques have been instrumental in identifying alterations in brain networks, providing a biological basis for the disorder. However, the interpretation of neuroimaging findings must consider the phenotypic heterogeneity of FND, including varying symptom severity, episodic vs. persistent symptoms, and symptom overlap. Neuroimaging has emerged as a key tool in elucidating the pathophysiological underpinnings of FND, with preliminary data suggesting predictive value in determining treatment response. Personalized treatment strategies based on neuroimaging findings face challenges, including the complexity of interpreting imaging data and the need for specialized skills. Future research efforts are essential to deepen the understanding of FND and develop targeted, effective treatments.