Although some research has addressed the thermal performance of green roofs in semi-arid regions worldwide, experimental data from Brazil remain scarce. This study contributes new evidence by evaluating thermal performance in the semi-arid climate of Northeast Brazil through a comparative analysis of environments covered with two extensive green roofs, planted with Crown-of-Frade (Melocactus zehntneri) and Babosa (Aloe vera), and a conventional ceramic tile roof. The primary motivation for this research was to investigate the feasibility of using accessible technology (in terms of materials and costs) to mitigate thermal discomfort, considering the population living in this climate. Assuming that green roofs can help minimize this discomfort, the study analyzed temperature (walls and ceilings) and humidity (ceiling) values inside the environments, along with external values of solar radiation, wind speed, temperature, and air humidity. The investigation period spanned from October 2015 to April 2016. The extensive green roof with Aloe vera showed the best results, reducing the indoor air temperature an average of 3.0 degrees C and up to 5.0 degrees C during peak hours, compared to the conventional roof. The study suggested that the climatic variables with the greatest influence on internal temperature were external temperature and humidity, while solar radiation and wind speed had little influence. The results demonstrate that extensive green roofs, using native species or those adapted to local climatic conditions, are a sustainable solution that improves internal thermal performance, potentially reducing energy consumption and enhancing quality of life in regions with high temperatures.