Through more than 20 years of investigating water leakage and condensation problems, the authors have observed that a high percentage of moisture problems related to masonry walls are associated with the interface between masonry veneer and fenestration systems. These problems are often associated with wall systems in aggressive exposures where the drainage system and air seal details at interfaces are not adequately considered by the designers and contractors. In many cases, drainage systems are not provided or not properly installed at joints between these systems. Air barriers and vapor retarders often are not sealed to fenestration systems or contain voids that permit the flow of air into the wall system. Problems can occur when anchors, lintels, support angles, and sill flashings are either not thermally improved or where the location of thermal breaks is not coordinated with the location of insulation within the walls. This paper outlines considerations for detailing the interface between masonry veneer over steel stud wall systems and fenestration systems. The fenestration systems reviewed in this paper include typical storefront or operable windows and curtain walls. Both masonry systems with the insulation positioned within the stud space and systems with the insulation positioned within the masonry air space are discussed.