This paper critically reviews the experimental and theoretical studies on the growth of ultrathin silica films onto metal single crystal substrates reported to date. The silica films on Mo(112) and Ru(0001) are discussed in more detail to demonstrate the key roles of the multi-technique approach and interplay between experiment and theory in the quest for understanding the atomic structure of the films. The results show the structural complexity and diversity of silica overlayers on metals, providing further information towards our understanding of the atomic structure, structural dynamics and physical and chemical properties of silica and related materials.