Stratospheric Aerosol Injection (SAI) has been projected to increase Earth’s reflectivity, and thus potentially reduce Earth’s temperature. However, SAI may affect Earth’s climate in various ways: altering of atmospheric circulation and biogeochemistry cycles, including stratospheric ozone. We will present results on the impacts of SAI on ozone density in simulations with a modified version of Earth System Model (DOE’s Energy Exascale Earth System Model version 3, E3SMv3). E3SMv3 has been modified to include full complexity chemistry mechanisms (Troposphere, Stratosphere, Mesosphere, and Lower Thermosphere, TSMLT) and a higher atmospheric top (80km, the default being 60km) to better simulate stratospheric dynamics and chemistry relevant to SAI simulations wherein sulfur dioxide (a precursor to sulfate aerosols) is injected into the lower stratosphere (Kang et al., 2024, in preparation). SAI can impact stratospheric ozone by a few mechanisms. For example, sulfur dioxide catalyzes ozone production. Also, with the increase in atmospheric reflectivity from stratospheric sulfate aerosols, there is less ultraviolet and visible light impacting ozone, reducing its photodissociation. Preliminary results suggest that E3SMv3’s simulation of the G6 sulfur scenario (where surface temperature from the unmitigated SSP5-8.5 scenario is reduced to that of the SSP2-4.5 scenario by SAI from 2020-2100) is found to significantly deplete stratospheric column ozone (SCO) over the Antarctic during its summer season. SCO there reaches a peak decline of about 52 DU and a mean decline of 6 DU in the month of October by 2100. This is in the lower range compared to results from other models. Over the Arctic, during March, there is an initial peak decline of 48 DU and a mean increase of 33 DU. This increase is significantly larger than other models which show varied responses. The projected increase in SCO over the tropics is generally consistent with other modeling studies. We plan to partition the role of different mechanisms that lead to the noted changes in stratospheric ozone. Nonetheless, these results point to the large uncertainty in the stratospheric ozone response associated with SAI and the need for more research to fully understand the implications of SAI on the climate system.