One of the leading causes for engineered cementitious composite's (ECC's) low modulus of elasticity (E) is the absence of coarse aggregate. The addition of crumb rubber (CR) to the mix aggravates the situation even further. The use of graphene oxide (GO) in cementitious composites, on the other hand, has been shown to improve the mechanical properties. Also, curing time affects the modulus of elasticity and the Poisson's ratio (v) of cementitious composites, among other things. The purpose of this study is to see how GO affects the long-term modulus of elasticity and Poisson's ratio of rubberized ECC. At 28 days and two years following water and ambient curing, cylinder samples of 300 mm height and 150 mm diameter were tested for E and v according to ASTM C496. According to the results, the elastic modulus and Poisson's ratio of all samples are favourably impacted by the addition of GO and the increase in curing time. © 2023 Author(s).