In this study, connection classification system is developed on the basis of previous classifications. Further, flexible connections are modeled by matrix displacement method. The effect of flexible connections are studied on gable frames. Firstly, flush end-plate connections with single row of bolts at the tension flange, are classified. The classification system was developed in this study. End plate connections whose moment-rotation curves are known arc classified on the basis of moments as FR (fully restrained) and PR (partially restrained) connections. Further, the connections are also classified by entering a plot with coordinates - Ratio of Moment at the connection and plastic moment and ratio of corresponding rotation and rotation at plastic moment. Depending on the location the connection can be classified. Secondly, for connections, the rotational stiffness is determined from the moment rotation curves and used in the computer code to implement flexible connections. The effect is studied on gable frames. For the loading and frame used there is not much variation in moments at the flexible joints due to connection flexibility and hence flush end plate connections can be used in gable frames effectively / Master of Science