An enantioselective total synthesis of (-)-galiellalactone has been accomplished. The key features of the synthesis involve the highly stereoselective construction of the cis-trisubstituted cyclopentane intermediate by a Pd(0)-catalyzed cyclization, the stereospecific introduction of an angular hydroxyl group by Riley oxidation, and the efficient construction of the tricyclic system of (-)-galiellalactone via a combination of diastereoselective Hosomi-Sakurai crotylation and ring-closing metathesis (RCM).