A confocal reflectance theta line scanning microscope demonstrates imaging of nuclear and cellular detail in human epidermis in vivo. Experimentally measured line-spread functions determine the instrumental optical section thickness to be $1.7\pm 0.1\mu \mathrm{m}$ and the lateral resolution to be $1.0\pm 0.1\mu \mathrm{m}$ . Within human dermis (through full-thickness epidermis), the measured section thickness is $9.2\pm 1.7\mu \mathrm{m}$ and the lateral resolution is $1.7\pm 0.1\mu \mathrm{m}$ . An illumination line is scanned directly in the pupil of the objective lens, and the backscattered descanned light is detected with a linear array, such that the theta line scanner consists of only seven optical components.