Optimizing generation and transmission expansion planning (GTEP) in power systems is imperative in response to critical challenges of climate change and the shift toward sustainable energy systems. In such a context, optimization techniques emerge as accurate tools to support power system expansion planning on regional and national scales. To contribute to this research stream, this paper introduces a novel bi-objective power system optimization model (PSOM) with the dual objectives of minimizing costs and reducing land use, particularly pertinent given the higher land use intensity of electricity production associated with renewable energy sources compared to nonrenewable ones. The applicability and reliability of the model are demonstrated through a detailed numerical study focusing on the Italian electricity system. The model outcomes provide actionable insights for policymakers and practitioners and pave the way for bolstering resilience and sustainability in the power sector, ensuring the implementation of environmentally responsible and cost-effective measures.