With the recent price increases, housing affordability has become a critical issue in Portugal. This situation requires the right policies to be taken. To support informed policymaking, this work presents an agent-based model of the Lisbon Metropolitan Area housing market that simulates interactions between heterogeneous households, a credit system, and a construction sector across rental and ownership markets. The model is grounded in empirical data from 2021 census and it was validated to ensure that it could replicate historical trends, including the 2008 financial crisis and the 2021–2023 period. It was then used to evaluate the potential effects of several policies proposed by the Portuguese political parties regarding the housing market. The model demonstrates how agent-based approaches can capture complex market dynamics and provide a transparent tool for evaluating the impacts of different housing policies.