Beam-column joints have a critical role in the integrity of structures. Due to reinforcement bars are anchored and lap into the column, joints are one of the most congested structural components. Placing and consolidating concrete in such structural frames imposes substantial technical challenges, which restricts the flow of coarse aggregates, thereby creating voids. Bond is the only way that transfers the tensile stresses between concrete and reinforcements. It is influenced by numerous factors such as the diameter of bars, concrete strength, embedded length of bars, concrete cover, reinforcement yield strength. In this research, another factor which is coarse aggregate size is considered, the role of coarse aggregate for bond strength of reinforced concrete was investigated experimentally using cylindrical samples (300*150mm) with centrally embedded 14 mm and 16mm deformed bar. A total of thirty-nine pull-out tests were carried out to determine the bond. Six mixes of concrete with similar compressive strengths but different coarse aggregate sizes of 37.5mm, 25mm, 19mm, 12.5mm, 9.5mm, and pure mortar were used with bar sizes of 14mm and 16mm. Compressive strengths of all concrete kept at the same level to study only the effect of coarse aggregate size on bond strength. Compressive strength, splitting tensile strength, and bond strength for normal strength concrete were studied. The bar was subjected to a monotonic axial load at the loaded end while the other end was embedded in concrete. Test results show the bond strength decreases significantly with a decrease in coarse aggregate size, there is a drop in bond strength especially at the pure mortar, despite having the same compressive and splitting tensile strengths. The research work outcome indicates, bond strength is highly affected by the coarse aggregate size, it has a significant difference between concrete contain the larger coarse aggregate size and pure mortar, which is about 38.65% and all specimenâ€™s failure mode was by pullout for those who have 5db embedment length. The bond strength for different coarse aggregate sizes was compared to equations proposed by different researchers and current codes. CEB-FIB 2010 codes, Esfahani & Rangan, Orangun et al and Darwin et al bond strength calculation equation works well only when the coarse aggregate size is 25mm and 19mm. Therefore, aggregate size is critical for bond strength when smaller coarse aggregates sizes are used.