The thickness and temperature dependence of the electrical resistivity of the 111 textured ultrathin aluminum metal films grown on 111 Si substrates using molecular-beam epitaxy have been investigated. For films with thickness <50 nm, the room-temperature value of resistivity—contrary to the predictions of existing theoretical models—is found to increase monotonically with thickness. In addition, the temperature dependence of these films exhibited a  metal-to-insulator transition at ~110 K. The studies of films using atomic force microscopy, x-ray photoelectron spectroscopy, and x-ray diffraction revealed that the observed anomalous thickness and temperature dependence of resistivity arise due to the formation of two-dimensional network of Al islands, and the low-temperature electric transport of such films could be explained using variable range hopping conduction.