The current state of ionospheric wind dynamo theory is reviewed. Observational and theoretical advances in recent years have permitted more accurate models of the dynamo mechanism to be presented than previously, which have lent further credence to the validity of dynamo theory as the main explanation for quiet-day ionospheric electric fields and currents at middle and low latitudes. The diurnal component of the wind in the upper E region and lower F region appears to be primarily responsible for average quiet-day currents, although other wind components give significant contributions. Observationally, there is a need for better spatial and temporal coverage of wind and electric field data. Theoretically, there is a need for further consideration of the mutual dynamic coupling among winds, conductivities, electric fields, and electric currents, and for better modeling of nighttime conditions.