Due to the significant increase in the demand for eco-friendly materials, conventional concrete and mildsteel have become less recommended due to the excessive CO2 emission of conventional concreteand corrosion issues of mild steel. Thus, other eco-friendly alternatives have risen to partially replacethese two materials. The first alternative is glass fiber reinforced polymers and the other is high volumefly ash concrete. This study investigates the bond-slip performance of glass fiber bars implanted inconventional and high volume fly ash concrete. The results were then compared to bond-slip resultsyielded from using mild steel. A total of twenty four cylinder specimens were tested in this study. Onelevel of high volume fly ash replacement of cement was used, 70%. Additionally, 13 mm (1/2 in.) and19 mm (3/4 in.) glass fiber and mild steel bars were investigated. The study was conducted followingthe recommendation of RILEM. The results indicated that, regardless the type of concrete, glass fiberhad less bond strength than that resulted from using mild steel.