The principal concern in structural design for earthquake forces is the lateral resistive system of the building. Braced frames are among the most common steel structures for resisting lateral loads. In most buildings, this system consists of some combination of horizontally distributed elements and vertical bracing elements. Failure of any part of this system or of connections between the parts can result in major damages to the building, including possibility of total collapse. Hence, in this book an introduction is made on related terms of an earthquake and simple calculation of its load based on the building code. Then, the most common braced systems and their specifications are explained. Moreover, a modeling and parametric calculation is made on a particular type of braced systems.