Abstract The properties of the fiber/matrix interphase in glass-fiber-reinforced composites can play a dominant rôle in governing overall composite performance. Understanding the interactions occurring at the interphase and being able to tailor them to give a desired composite property are of great importance. In this paper, a singlefilament model of a commercial glass-fiber-reinforcement manufacturing process was used to apply methacryloxy and amino silanes with one, two, and three silanols (mono-ol, diol, and triol) to two different glass fibers in a molecular model. Surface analyses by angular-dependent X-ray photoelectron spectroscopy (ADXPS), electric-kinetic analysis (EKA), and contactangle measurements were used to characterize the surface coatings. The micro-indentation technique was used to evaluate fiber/matrix interfacial adhesion. Changes observed in surface chemistry, micromechanics, and composite properties as function of the silanol type are correlated.