This paper reports the durability performance of engineered cementitious composites (ECC) containing high volume of palm oil fuel ash (POFA) when subjected to accelerated alkaline environmental conditions. Three sets of ECC mixtures with water–binder ratios of 0.33, 0.36, and 0.38 were prepared, and for each set, the ECC mixtures were proportioned to have varying POFA contents equaling to 0, 0.2, 0.4, 0.8, and 1.2 from the mass of cement. The ECC bars were cured in water at 80 °C for 24 h. After initial