With the introduction of high intensity synchrotron radiation sources, X-ray diffraction has become established as a powerful probe of surface crystallography. Many surface structures have been solved with progressively larger unit meshes. More recently, the technique has been extended to provide real time monitoring of surfaces during epitaxial growth. The weak scattering of X-rays allows a simple interpretation of measured intensities through the kinematic approximation, thus giving a direct and immediate insight into the atomic geometry. The technique is not limited to the solid-vacuum interface and has potentially wide application. Thus it may be used to monitor the growth in a OMVPE reaction chamber and can probe atomic arrangements at buried interfaces such as a delta doping layer. The use of X-ray scattering for the study of epitaxial growth on semiconductor surfaces is reviewed with examples taken from recent work.