Open Access gained a lot of importance in the last decades and is now strongly supported by many scientific organisations and funders in several countries. But as the movement is becoming more and more mainstream, a new question arises that is rarely addressed : how open exactly is open access? or more precisely: how open is it to the diversity of scientific cultures, publishing languages and scholarly communication practices that exist in the academic landscape? Some scholars have been using the concept of 'bibliodiversity' to capture this concern and promote a different way to foster open access to academic publications. In my presentation, I will explore how the concept of bibliodiversity is particularly fruitful to guide open access initiatives and policies, particularly in the European context.