The role of frustrated Lewis pairs (FLPs) as ligands in gold(I) catalyzed-reactions has been computationally investigated by using state-of-the-art density functional theory calculations. To this end, the nature of (P,B)-FLP-transition metal interactions in different gold(I)-complexes has been first explored in detail with the help of the energy decomposition analysis method, which allowed us to accurately quantify the so far poorly understood AuB interactions present in these species. The impact of such interactions on the catalytic activity of gold(I)-complexes has been then evaluated by performing the Au(I)-catalyzed hydroarylation reaction of phenylacetylene with mesitylene. With the help of the activation strain model of reactivity, the factors governing the higher activity of Au(I)-complexes having a FLP as a ligand as compared to that of the parent PPh3 system have also been quantitatively identified.