Nowadays, cooling demand in the building sector is increasing in cooling-dominant climates because of extreme heat waves reinforced by climate change. As the demand for thermal comfort in buildings continues to grow, energy consumption increases accordingly. The application of phase change materials (PCM) to building envelopes can improve thermal energy storage, thus they can be used to increase the thermal mass of buildings. This article shows the efficiency of using PCMs to mitigate building cooling demands in eight cities representing the Mediterranean region: Al Hoceima (Morocco), Malaga (Spain), Marseille (France), Taher (Algeria), Naples (Italy), Tripoli (Libya), Ankara (Turkey), and Port Said (Egypt). The energy performance of three types of building: single-family, collective housing and hotel housing, built with hollow bricks, with and without PCMs, is evaluated in these cities using a numerical model based on the apparent heat capacity. A wide range of PCM melting temperatures is studied (from 22 °C to 32 °C). The results confirm that climate profoundly influences the storage/release process of PCMs. Regardless of the building typology, energy savings can reach 56% in the North-East Mediterranean cities using a PCM with a 26 °C melting temperature, while no energy savings have been noted for the South-East cities. Finally, a correlation between the energy savings and the Cooling Degree Day is demonstrated, resulting in the recommendation of a PCM with a 26 °C median melting temperature in a given location.