This paper deals with the comparison of thick and thin shel1 theories for buried orthotropic cylindrical shell excited by incident shear wave. For this purpose only axisymetric response has been investigated and a perfect bond between the shell and surrounding medium has been assumed. The nature of variation of differences between the two shell theories results has been discussed for different soil conditions and angles of incidence of the shear wave. The differences in results as obtained by varying orthotropic parameters have been compared with the changes in the results of thick and thin shell theories. It is realized that shell response is significantly influenced by variation in the values of the orthotropic parameters rather than the choice of shell model.