Oro-pharyngeal dysphagia is a common symptom in patients with Parkinson's disease (PD) and related disorders, even in their early stage of diseases. Dysphagia in these patients has been underdiagnosed, probably due to poor the self-awareness of the conditions and the underuse of validated tools and objective instruments for assessment. The early detection and intervention of dysphagia are closely related to improving the quality of life and decreasing the mortality rate in these patients. The purpose of this paper is to give an overview of the characteristics of dysphagia, including the epidemiology, pathophysiology, and clinical symptomatology, in patients with PD compared with other parkinsonian disorders and movement disorders. The management of dysphagia and future research directions related to these disorders are also discussed.