In this letter, atomically resolved scanning tunneling microscopic (STM) images obtained from monolayer SiO 2 /Mo(112) are presented. The results are consistent with a previously proposed structural model of isolated [SiO 4 ] units based on vibrational features observed by high-resolution electron energy loss spectroscopy (HREELS) and infrared reflection–absorption spectroscopy (IRAS), and oxygen species identified by ultra-violet photoemission spectroscopy (UPS). These results are inconsistent with a structural model that assumes a two-dimensional (2-D) [Si–O–Si] network. These data illustrate that a metal substrate, although coated with an oxide thin layer, can be directly imaged at the atomic-scale with STM.