MgGeN2 is a type II-IV-V-2 semiconductor with a wide band gap which have previously been studied in bulk, monolayer, and multilayer form. We have investigated single wall MgGeN2 nanotubes in different orientations and diameters by ab initio calculations. It was found that the band gap is strongly dependent on the type and diameter of the tubes, ranging from 2.1 to 2.6 eV. Moreover, the migration of electrons is favored instead of holes. The obtained results also suggest that the radius- and orientation-dependent single wall MgGeN2 nano tubes are promising for optoelectronics and photocatalysis.