It is widely accepted that the overall composite properties are influenced by the fiber/matrix interface. By changing the interface chemistry and architecture, one can manipulate the fiber/matrix interaction, failure mode, and the macroscopic properties. Fiber manufacturers apply a sizing package to protect the fibers during handling and weaving, as well as improve the fiber/matrix interface. However, the exact chemical composition is proprietary, and the complex chemistry have motivated many studies to explore the roles of their component. Organosilanes, such as (3-glycidoxypropyl)trimethoxysilane (GPS) and (3-aminopropyl)triethoxysilane (APES), have been identified as the primary adhesion promoting component for glass fiber to epoxy-based resins, and some modelling work suggests that a uniform monolayer-type coating can improve the interface properties. This study reports on the progress towards gaining insight on methods to control the organosilane architecture to create the monolayer-type coatings on S-glass fiber and understand the coating’s role in the S-glass/epoxy interface properties. A chemical vapor deposition method was chosen to deposit these GPS and APES onto the S-glass surface to create an agglomeration-free thin film. This was compared to thicker coatings of these organosilanes that were deposited using a liquid bath technique. The S-glass/epoxy interface properties were evaluated for these systems using a single fiber pullout method. By understanding the effects of the chemistry and architecture of the interface as well as how to control it, one gains the ability to better tailor the interface to optimize the material for the application specific needs.