By applying spherical harmonic analysis to the ozone data obtained from the Nimbus-7 solar backscattered UV-radiation (SBUV) measurements for the period from November 1978 to October 1980, the following features of the semi-annual oscillation (SAO) in stratospheric ozone are revealed: (1) The equatorial ozone SAO has a broad maximum of the order of 0.5 (mixing ratio in &mgr;g/g) between the 10 mb and 3 mb levels, an the maximum shifts downward from 1 mb in June (and December) to 40 mb in November (and May). (2) Amplitudes of polar ozone SAO's are larger than that of the equatorial SAO with a major maximum at 2 mb which is 2 &mgr;g/g at 75¿N and 0.8 &mgr;g/g at 75¿/S, respectively. (3) The inverse phase between the polar and tropical SAO which occurs around the 3 mb (~40 km) level can be interpreted in terms of the temperature dependent ozone chemistry and the poleward meridional transport of ozone by dynamical processes in the atmosphere.