Halogenation reactions of alkenes are useful tools in synthetic organic chemistry. These provide access to a broad range of various structural motifs, and the incorporation of one or two halogen atoms into the molecule allows for subsequent functional group manipulation. In this chapter, the focus is placed on the most significant developments of the past two decades with emphasis on methods that exhibit either broad substrate scope or unique entries into classes of compounds relevant to complex molecule synthesis. Besides dihalogenation and hydrofluorination reactions, the important areas of oxy-, amino-, and carbohalogenation reactions are discussed with a strong focus on recent developments in stereoselective method.