The primary goal of this research is to investigate the role of modal resources in policy discourse. To this end, the 2030 Agenda for Sustainable Development, issued by the United Nations member states in 2015 representing a global comprehensive plan for the transformation of the world, is critically analyzed with a particular focus on examining the frequency and strategic functions of modal verbs in conveying certain interpersonal meanings that contribute to the influential delivery of messages in the Agenda. The corpus of the study comprises the full transcript of the 2030 Agenda; a corpus-assisted critical discourse approach was adopted for data analysis. The theoretical framework relies upon Fairclough's dialectical-relational approach (2015) in combination with the corpus linguistics tool AntConc 3.5.9. Both quantitative and qualitative methods were employed for arriving at an objective interpretation of the policy text. Research findings reveal that modals with high intensity are more predominant than modals with low intensity and that the main categories of modal verbs that characterize the data are ability, possibility, obligation, necessity, volition and prediction. These modal resources are used to capture the intensity of the policymakers' views and attitudes with regard to the actions required for the world to adopt and implement the 2030 Agenda. The study concludes that modal markers are deployed for emphasizing the seriousness and urgency of the issues in the 2030 Agenda.