• Social media are new channels to improve stakeholder engagement. • Through Twitter's posts, the 17 UN SDGs result in different stakeholder engagement. • Tweet characteristics (content, hashtags, link, industry and country) affect stakeholder engagement. • Significant SGDs are partnerships for the goals, climate action, reduced inequalities, life below water, life on land, and gender equality. Social media, based on information and communication technologies (ICTs), work as new channels to exchange information among stakeholders and play role in improving stakeholder engagement. Considering this aspect, we investigated the characteristics of social media posts that result in higher stakeholder engagement in the European context, and we determined which of the 17 United Nations (UN) Sustainable Development Goals (SDGs) result in greater stakeholder engagement. We apply chi-square automatic interaction detection (CHAID) method to categorize social media posts based on their engagement levels. We analyzed tweets that companies published in 2019 on Twitter that also publish sustainability reports on Global Reporting Initiative. The final sample is based on 3,045 tweets from 173 firms of different industries and countries. We found that tweet characteristics such as content type (SDGs), use of hashtags, existence of link, number of characters, industry type and country of a firm significantly influence stakeholder engagement rates. The most significant SGDs are partnerships for the goals, climate action, reduced inequalities, life below water, life on land, and gender equality. This is the first study which considers the communication of SDGs by firms through social media to determine which SDGs are considered most relevant and promote higher stakeholder engagement. [ABSTRACT FROM AUTHOR]