In this study, as a developing European economy, the Turkish building sector is assessed for potential CO2 emission reduction with a bottom-up modelling framework with a time horizon starting from 2015 until 2050. Three emission mitigation policies are studied for their emission reduction potentials, namely, increasing the usage rate of energy-efficient appliances, improving the energy performance of the building envelope in existing buildings, and increasing the use of energy-efficient heating and cooling systems. Based on these potentials, three emission reduction scenarios for 5%, 10%, and 21% compared to reference cases are designed and implemented. It is shown that much higher energy savings levels, 6%, 12%, and 28%, are achieved. It has been found that the cost-effectiveness of emission reduction scenarios depends on the policy mix as well as the future emission intensity of the electrical energy consumed, which can reduce the cost of mitigation down to the range of 100–200 USD/tonne CO2. •GHG emission mitigation potential of buildings in Turkey until 2050.•Projection of GHG emissions and energy demands of buildings up to 2050.•Bottom-up and techno-economic modelling of buildings’ sector using TIMES framework.•Dynamic partial equilibrium, piecewise linear optimisation model.•The impact of GHG emission intensity of electricity on the cost of mitigation.