In this research, SDG standards are mapped to the environmental, social, and governance (ESG) pillars through Triple-Bottom Line (TBL) groupings based on the Global Reporting Initiative (GRI) guidelines and accounting items, which allow SDG standards to be harmonised with the ESG pillars. Two methodologies developed in the literature for classifying SDG standards into TBL groupings were also used to create a ranking scheme. This scheme can help companies determine which SDG standards are most important for their sustainability reporting. Companies report on the steps they have taken towards sustainability and the sustainability aspects of their operations in their ESG sustainability reports. In many cases, their reporting includes information on SDGs, which, like ESG reporting, does not have a standard disclosure methodology, so announcements are made with different information, in different formats, by different companies. To make SDG reporting more consistent, harmonisation with existing ESG reporting methodologies could be identified as a forward step in this field because it would help to produce more informed, consistent SDG reporting. In addition to integrating SDGs into ESG reporting methodologies, SDGs also could be integrated into ESG scoring methodologies, which would be more relevant to stakeholders and the stock market. The paper will review ESG reporting and scoring methodologies, with a particular focus on which methodology is most appropriate for harmonisation. By defining the integration methodology, the study contributes to the public policy discussion about sustainable reporting.