Structured illumination microscopy in thick fluorescent samples is a challenging task. The out-of-focus fluorescence background deteriorates the illumination pattern and the reconstructed images suffer from noise artifacts. We present a combination of structured illumination microscopy with line scanning. This technique reduces the out-of-focus fluorescence background, which improves the modulation and the quality of the illumination pattern and therefore facilitates the reconstruction. Here we present super-resolution, optically sectioned images of a thick fluorescent sample, revealing details of the specimen’s inner structure.