Many years have passed since corporate social responsibility (CSR) and the disclosure of non-financial information (NFI) aroused interest in very few organizations (Hąbek & Wolniak, 2016). Today, they are part of the main priorities for the most important companies in the world, and they are seen as an important part of the strategy due to the many benefits associated with them (Castilla-Polo & Sánchez-Hernández, 2020). In the last decades, it has become evident the relevance that NFI reporting has worldwide. It can be seen through the evolution of the issuance of this type of reports. In 2002, 45% of the G250 companies published a separate report, 20 years later, the numbers show that 96% of the G250 companies report on ESG matters. Reporting NFI, that started as a voluntary action from firms, is becoming a critical aspect for them. The EU Directive 2014/95/UE was enacted by the European Parliament in 2014. This directive attempted to improve transparency by requiring firms to report information on six topics: environmental; social; employee matters; respect for human rights; anti-corruption; and bribery matters. On the 5th of January (2023) the Directive (EU) 2022/2464 (European Parliament, 2022) came into force and will require approximately 50.000 large and listed SMEs in total to report on sustainability. These directives are sending a clear message to organizations about the political commitment with transparency, extent, quality, and liability of NFI. NFI reporting has gained great prominence not only because of the increase of the legislation, but also due to the growing interest of different stakeholders. They demand that companies go beyond their legal obligations, take responsibility for their impacts, and increase transparency (Hąbek & Wolniak, 2016). Although there has been progress in terms of quality and extent of the reports, especially since the directives were enacted, there is still a long way to improve. The relevance that sustainability reporting has nowadays for firms makes it a crucial object of study. The NFI reports still lack maturity when compared to the financial statements (EY, 2022). There are still challenges regarding the assurance, the heterogeneity and incomparability of the reports. Research that focuses on what improves quality and quantity of the report is needed (Ali et al., 2017), as there is still a lot of progress to make in this matter. The main objective of this doctoral dissertation is to deepen and advance the knowledge on the topic of NFI reports and the drivers for their improvement in terms of quantity and quality. First, we want to study the evolution of the topic, and to structure the knowledge to be able to identify the different lines of research along with their main contributions and gaps. Then, determine which is the influence as a determinant of regulation and reputation on the firm’s NFI report. Finally, our last goal is to study which is the effect that the board composition has on NFI reports. The sample of our study includes the firms that were part of the Ibex35 in the period 2015-2019. We employ different methodologies: bibliometric analysis; and panel data analysis techniques. For the bibliometric analysis we performe co-authorship, co-occurrence, citation, bibliographic coupling, and co-citation analyses. For the panel data we use three different methods: the Pooled OLS, Fixed Effects (FE) and Random Effects (RE).