We apply synchrotron X-ray analysis techniques to probe the surface structure of GaN films during synthesis by metallorganic chemical vapor deposition (MOCVD). Our approach is to observe the evolution of surface structure and morphology in real-time using grazing incidence X-ray scattering (GIXS). This technique combines the ability of X-rays to penetrate the chemical vapor deposition environment for in situ measurements, with the sensitivity of GIXS to atomic scale structure. Examples are presented from some of our studies of growth modes and surface evolution as a function of process conditions that illustrate the capabilities of synchrotron X-ray analysis during MOCVD growth. We focus on studies of the homoepitaxial growth mode, island coarsening dynamics, and effects of impurities.