Aim: The objective of this study is to carry out a systematic review of the scientific literature on the whole of the biodiversity of green roofs to (i) elucidate the role of green roofs in supporting biodiversity in the city by focusing on quantitative data, (ii) and to explore the factors influencing the biodiversity of green roofs. Method: We conducted our search in Web of Sciences using all available databases. The key words used are: (“green roof*” or rooftop* or greenroof*) and (biodiversity* or plant* or fauna or wildlife). In total, 2392 articles came out as search results. A first selection was made based on titles and abstracts, or even the entire article, to identify the articles that really fall within the subject. In total, 154 articles were considered relevant for our study. Results: Our review shows: - The lack of knowledge on the biodiversity of green roofs with recent consideration (around 2010). - The important contribution of green roofs in maintaining urban biodiversity through three influencing factors: characterization, uses, design. - That there are very few studies concerning soil biodiversity, unlike aerial biodiversity (e.g. plants, bees, birds) within green roofs. Conclusions: Green roof construction guidelines should integrate soil communities into their design and aim to be heterogeneous at roof and landscape levels, with the aim of supporting soil biodiversity and creating sustainable habitats.