The central topic of the ROMCIR (Reducing Online Misinformation through Credible Information Retrieval) 2021 workshop, as part of the satellite events of the ECIR (European Conference on Information Retrieval) 2021 conference, concerns providing access to users to credible and/or verified information, to mitigate the information disorder phenomenon. By “information disorder” we mean all forms of communication pollution, from misinformation made out of ignorance, to intentional sharing of false content. In this context, all those approaches that can serve to the assessment of the credibility of information circulating online and in social media, in particular, find their place. This topic is very broad, as it concerns different contents (e.g., Web pages, news, reviews, medical information, online accounts, etc.), different Web and social media platforms (e.g., microblogging platforms, social networking services, social question-answering systems, etc.), and different purposes (e.g., identifying false information, accessing information based on its credibility, retrieving credible information, etc.).