First-order (small roughness amplitude) scattering theory is applied to obtain sea clutter cross sections in terms of mean-squared height spectrum of the sea surface. The results are in remarkably good agreement with observations for vertical polarization at

, and

-bands. Modification of the calculation to take into account the larger scale structure of the sea surface yields reasonable agreement for horizontal polarization at

- and

-bands but is less successful for the cross-polarized and horizontal cross sections at

- and

-bands.