Global calculations of stratospheric HOx, Clx, and NOxare presented which include the effects of planetary albedo and diurnal and seasonal variations of the insolation. Comparisons are made with a wide range of atmospheric measurements at different latitudes and altitudes. Agreement between theory and observations is generally within a factor of 2. The theory appears to explain adequately the major features of latitude and seasonal distributions of NO2and HNO3. The results indicate that mesospheric OH makes an appreciable contribution to the total OH column abundance and strongly suggest that nitrogen oxides exist principally in the form of HNO3at high latitudes in winter. There are difficulties in reconciling OH, ClO, and O3observations in the upper stratosphere.