Channelopathies are a recently delineated, emerging group of neurologic disorders united by genetically determined defects in ion-channel function. These disorders are characterized by a prominent genetic and phenotypic heterogeneity that can make them challenging and bewildering to understand. This systematic review attempts to categorize these disorders according to their predominant clinical manifestations (i.e., myotonia, weakness, migraine, ataxia, epilepsy, and movement disorders) within the context of what is presently known about the molecular basis of recognized clinical syndromes. Areas of both genetic and phenotypic overlap are highlighted. The review is intended to assist clinicians in enhancing their diagnostic acumen and in targeting specific genetic tests.