Abstract Purpose This paper aims to analyse the prevalence of emotional and rational appeals in social advertising campaigns. There are studies about the effectiveness of these tones of appeals in social marketing, but there is no evidence about their prevalent use in social advertisements. Design/methodology/approach The authors conducted a content analysis of forty social advertisements promoting attitudes and behaviours regarding social causes. The selected ads were in video format and were extracted from the YouTube channels of Portuguese governmental and non-governmental organisations. The ads were coded according to the characteristics of each tone of appeals and classified as emotional, rational or a mix of both. Findings The authors classified 25 social ads as rational appeals, 8 as emotional and 7 as a mix of both appeals. The results of the research show that social marketers have preference for the use of rational tone in social advertising campaigns. Originality/value This study shows that there is a disruption between theory and practice in social marketing, considering the higher prevalence of rational appeals in contexts where theory recommends emotional appeals for higher effectiveness. This evidence is surprising, considering a previous study that evidenced a higher use of emotional appeals in advertising connected to social causes than in commercial advertisements. This paper focus on how practice may disrupt theory and explores possible reasons for the phenomenon.