Gold nanoparticles (NPs) deposited on select metal oxides exhibit unique catalytic properties, though bulk gold is almost inert as a catalyst. The catalysis by supported gold NPs can be created by the selection of the support materials, the control of the size of gold NPs, and the strong contact of gold NPs with the supports. Particularly, gold NPs should be smaller than 10 nm in diameter and hemispherical in shape, because the perimeter zone around gold NPs is often the active sites for many reactions. Since the elucidation of the origin of the catalysis by supported gold NPs has become a focal point of research on catalysis by gold, the interplay of theoretical calculations and reasonable experiments in catalysis by supported gold NPs has been attracting growing attention. This article mainly summarizes our recent examples of such interplay. (C) 2015 Elsevier B.V. All rights reserved.