Observations of the molecular gas surrounding the biconical H II region S106 reveal a approx.100 M/sub sun/ disk constraining the development of the ionized region. Two CO peaks are seen in the equatorial plane of the biconical nebula on opposite sides of a near infrared source thought to be the exciting star for the H II region. Although no systematic velocity gradient is seen for the cloud as a whole, there is a small velocity shift of approx.2 km s/sup -1/ in the CO emission from the two peaks. We develop a model for S106 with a BO exciting star situated in a dense neutral disk which dominates the dynamics of the nebula. Isothermal expansion of freshly ionized material from the disk drives a supersonic flow of plasma which supplies gas to the two lobes of the H II region. The observed biconical morphology, electron density distribution, and high-velocity outflow of ionized gas can be reproduced by the model.