Seafloor topography influences ocean circulation in two basic ways. First, it steers ocean flows. Second, it provides barriers that prevent deep waters from mixing, except within deep passageways that connect ocean basins or in hydraulically controlled overflow regions. This paper explores the impact of both of these processes on ocean circulation. The examples highlighted here were among the broad range of topics explored at a workshop on “Ocean Circulation, Bathymetry, and Climate,” held at Scripps Institution of Oceanography in October 2002.