The Geophysical Fluid Dynamics Laboratory's SKYHI general circulation model (GCM) including a new detailed stratospheric photochemistry module has been integrated for over 14 years with an imposed zonally symmetric momentum source designed to force a realistic quasi-biennial oscillation (QBO) in the tropical stratosphere. The GCM features an internally consistent calculation of the annual stratospheric circulation cycle and exhibits realistic extratropical stratospheric interannual variability, making it appropriate for the detailed investigation of QBO/annual cycle interactions. The simulated ozone QBO is generally realistic in the tropics and subtropics, and, in particular, the QBO in total column ozone agrees quite well with that derived from satellite observations. A detailed analysis of the QBO modulation of the zonal-mean ozone budget has been performed. The advective effects of the QBO-induced residual mean circulation are found to be strongly dependent on season, in accord with recent results from some two-dimensional model studies <Jones et al., 1998; Kinnersley and Tung, 1998>. In addition, the QBO modulation of explicitly resolved eddy transport in the GCM is found to make a significant contribution to the ozone budget, and this helps account for the strong seasonal synchronization of the ozone QBO. ¿ 1999 American Geophysical Union