Lesion studies represent a core approach to investigate the functional role of specific brain regions. Especially asymmetry research benefits from this method since the impact of left- and right-hemispheric lesions can be directly compared to unravel the functional significance of each brain side. A large number of permanent or reversible lesion methods are available that differ in applicability and reliability depending on size and developmental stage of the neuronal target structure. This chapter presents an overview of the different methods and provides a short and general methodological guide. It also discusses principal advantages, drawbacks, and problems of lesion studies that should be considered when selecting the appropriate method or interpreting results.