A woofer–tweeter adaptive optical structured illumination microscope (AOSIM) is presented. By combining a low-spatial-frequency large-stroke deformable mirror (woofer) with a high-spatial-frequency low-stroke deformable mirror (tweeter), we are able to remove both large-amplitude and high-order aberrations. In addition, using the structured illumination method, as compared to widefield microscopy, the AOSIM can accomplish high-resolution imaging and possesses better sectioning capability. The AO