The global trend of increased sewage sludge (SS) generation, driven by population growth, economic development, and the expansion of sewage collection and treatment services, has heightened environmental and public health concerns, particularly after the detection of the COVID-19 virus in SS. These factors underscore the importance of developing safe, rational, and efficient methods for the utilization or recycling of SS. Incineration has been evaluated as an alternative to landfilling. Although it is not waste-free, it generates SS dry solids amounts, which can be used as supplementary cementitious materials. This study evaluated the effect of incineration temperature on the chemical properties of sewage sludge ash (SSA) and assessed their reactivity in cement pastes. To this end, loss of ignition, X-ray diffraction, energy-dispersive X-ray fluorescence, and pozzolanicity were performed on the obtained SSA. Based on these results, SSA incinerated at 650°C and 800°C were selected for producing cement pastes. These SSA were used to replace 10 % of the portland cement by mass and compared with cement-based pastes containing the same amount of fly ash. The SSA produced in this study were classified as nonpozzolanic, and the incineration temperature influenced their chemical characteristics. Reactivity of the SSA was observed with the portlandite released during cement hydration, and the mechanical behavior of SSA pastes was comparable to that of the pastes made with fly ash.