In this article, catalyst systems for homogeneous epoxidation are reviewed with an emphasis on reaction elements that are of foremost interest to synthetic chemists: catalyst systems, substrate scope, and selectivity. General mechanisms and reaction conditions for each catalyst system are discussed followed by more detailed summaries of the epoxidation of specific classes of olefins: unfunctionalized terminal olefins, cis‐disubstituted, trans‐disubstituted, tri‐ and tetrasubstituted olefins, functionalized olefins including allylic alcohols, and electron‐deficient olefins. Major classes of catalysts addressed are early transition metal‐peroxo forming catalysts (inclusive of the Sharpless titanium tartrate catalyst for the asymmetric epoxidation of allylic alcohols and MTO), metal‐oxo forming catalysts (such as metalloporphyrin and Jacobsen/Katsuki salen catalysts), dioxirane and oxaziridine catalysts, Lewis acid and lanthanide catalysts, phase‐transfer and polyamino acid catalysts, and finally sulfur ylide catalysts for the formation of epoxides from aldehydes. Dedicated to Professor K. Barry Sharpless on the occasion of his 60th birthday.