Glass Fiber Reinforced Polymer (GFRP) structural sections find application in various construction projects, including foot, road, and rail bridges, rapidly deployable structures, stand-alone low-mass structures constructed above the buildings, and prefabricated buildings. Steel-like sections are nowadays manufactured through the pultrusion technique and are used in framed structures. The GFRP sections can be connected via bonding, bolting, or hybrid (a combination of bonding and bolting) using cleats, plates, cuffs, etc. Cleats with bolted connections are interesting due to their fast employability. This paper discusses an exterior beam-column flange cleated connection using GFRP I-Section as the beam and the column. The study was conducted experimentally under monotonic loading and numerically using finite element software ABAQUS. A comparison is made between the rotational stiffness offered by the stainless-steel cleat and the GFRP cleat on the GFRP beam-to-column joint. The effect of GFRP cleat thickness and bolt diameter on the performance of beam-to-column joint is also assessed. Load-deflection, Moment-rotation and Failure modes are studied for different cleat thicknesses, cleat materials and bolt diameters. It was observed that there is a 42.01% increase in the rotational stiffness when a 10 mm GFRP cleat is used over a 6 mm GFRP cleat. Steel cleats exhibited 38.35% greater stiffness when compared to GFRP cleats of the same thickness. By increasing the bolt diameter from 8 to 14 mm, stiffness showed a marked increase of 85.78%.