The construction sector is responsible for 39% of the global energy- and process-related CO2 emissions, of which 11% is due to the production of construction materials. The municipality of the city of Leiden in the Netherlands has set goals to build 17,000 new dwellings between 2020-2030 and to lower its overall carbon footprint. In this study, the environmental impact reduction potential of wood construction systems (WCSs) for the construction of 17,000 mid- and high-rise residential buildings in Leiden was explored. The two WCS alternatives studied are cross-laminated timber (CLT) construction systems built with either the modular or flatpack method. A number of sustainability choices expected to lower the environmental impact of WCSs through prolonged biogenic carbon retention time were quantified in a scenario-based life cycle assessment (LCA). These choices included high-end reuse of WCSs, wood material downcycling into particleboards, extending the building service life (BSL), dwelling size reduction, and wood resource country selection. Results showed a maximum hypothetical impact reduction of 92.3% for modular CLT and 91% for flatpack CLT WCSs. This hypothetical reduction was achieved when all sustainability choices were combined. The selected scenarios used and the level of detail of the LCA model do not fully align with current trends in the construction- and housing sector. Therefore, the actual realization of the impact reductions presented should not be perceived as highly feasible. Two originally included WCS alternatives consisting of CLT and timber frame construction (TFC) hybrids could unfortunately not be quantified due to technical issues with the used LCA modelling software.