Measurements of angular scattering due to surface roughness are taken from a 24-layer dielectric mirror and compared to theory. In addition, the top surface roughness of the multilayer stack is analyzed from Talystep profilometer measurements. This roughness data is used to obtain a spectral density function to be used in a vector multilayer scattering theory. When this is done, it is found that the theory, using the experimentally obtained roughness spectral density function, agrees remarkably well with the measured angular scattering data. This is especially true if care is taken to differentiate between particulate and roughness scattering. The theory uses three multilayer stack models to incorporate possible effects of different levels of correlation between interfaces of the stack. The stack was produced by Optical Coating Laboratory Incorporated.