The circulation of Tampa Bay is investigated using a high-resolution, three-dimensional, density-dependent, finite volume coastal ocean model (FVCOM) that includes Tampa Bay, the intracoastal waterway, and the inner portion of the west Florida continental shelf. Model performance over the three-month interval, September to November 2001, is assessed against available tide gauge and velocity profiler data before using the model to describe the circulation as driven by rivers, tides, and winds. Because of a mean wind velocity vector directed down the estuary axis, we ran a parallel model experiment without winds to distinguish the estuarine circulation by gravitational convection from the mean wind effects. With or without winds, Tampa Bay exhibits a robust, two-layered estuarine circulation that concentrates on the deep channels. The mean outflow at the surface tends to converge on the channels where the free surface elevation is locally minimum. The mean inflow near the bottom also concentrates in the channels where the baroclinic pressure gradient force is largest. Geometry thus guides the mean circulation and salinity distributions. At the Tampa Bay mouth, mean outflows exist both in the deeper Egmont Channel and the shallower South Pass, whereas a mean inflow is limited to the Egmont Channel. A residence time based on the Egmont Channel influx is estimated to be about 100 days. Consistent with previous studies we conclude that gravitational convection is a major contributor to the water property distributions of Tampa Bay, and that the FVCOM is suitable for estuary/shelf interaction studies.