This article examines corporate sustainability reports, the standards they use, and their connection to performance on the sustainable development goals (SDGs) from firms in the main Spanish stock index. The investigation was performed through an exploratory, descriptive, analytic study as well as examination of the disclosure and performance on the SDGs after Law 11/2018 went into effect in Spain. The study methods used include parametric correlations that explain the associations between the global reporting initiative (GRI) and environmental, social, and governance (ESG) standards and the level of performance on SDGs/ESG in the sustainability reports.We found that all firms present their verified sustainability reports, that the level of ESG information is above 75%, and that the GRI is the sustainability standard used.Further, all firms contribute on average a 75% level of information on all goals and on each of the 17 goals for the 2030 Agenda. We obtain significant analogies in level of disclosure of GRI-ESG information and level of performance on the SDGs/ESG. In addition, the higher the level of information on environmental GRI standards, the better the firm's position in the environmental SDG ranking.