This article provides a comprehensive review of ligand effects in homogeneous gold (Au) catalysis, highlighting the progress made in the field over the past decade. The authors emphasize the role of Au as a mild, carbophilic Lewis acid in activating carbon-carbon π-bonds and discuss various reactions that have been developed using this property. The review covers a wide range of synthetic reactions, including enyne cycloisomerizations, hydroarylation of alkynes, and hydroamination of C-C multiple bonds. It also explores the use of relativistic effects to understand the reactivity of Au catalysts and the control of selectivity through ligand, counterion, and oxidation state effects. The article is organized by reactivity patterns and substrate classes, with a focus on ligand effects on enantioselective catalysis. Specific examples of catalyst choice and its impact on reaction pathways, including diastereoselectivity, regioselectivity, and chemoselectivity, are discussed in detail. The review concludes by discussing the potential of N-heterocyclic carbene (NHC) Au(I) complexes and the application of Au catalysts in polymerization chemistry.This article provides a comprehensive review of ligand effects in homogeneous gold (Au) catalysis, highlighting the progress made in the field over the past decade. The authors emphasize the role of Au as a mild, carbophilic Lewis acid in activating carbon-carbon π-bonds and discuss various reactions that have been developed using this property. The review covers a wide range of synthetic reactions, including enyne cycloisomerizations, hydroarylation of alkynes, and hydroamination of C-C multiple bonds. It also explores the use of relativistic effects to understand the reactivity of Au catalysts and the control of selectivity through ligand, counterion, and oxidation state effects. The article is organized by reactivity patterns and substrate classes, with a focus on ligand effects on enantioselective catalysis. Specific examples of catalyst choice and its impact on reaction pathways, including diastereoselectivity, regioselectivity, and chemoselectivity, are discussed in detail. The review concludes by discussing the potential of N-heterocyclic carbene (NHC) Au(I) complexes and the application of Au catalysts in polymerization chemistry.