Relevance. The article is devoted to the study of persuasive linguistic indicators in social advertising, one of the speech practices (genres) of the discourse of social harmony, which is considered to be in contrast to aggressive discourse as a set of speech practices aimed at stabilizing social relations and reducing social tension. The relevance of the work is explained by the growing role of discursive means, in particular in social advertising, which are aimed at persuading the target audience of the need to change their attitudes, opinions, and behavior in the context of digitalization and information overload. Problems. The article presents linguistic persuasive indicators used in modern social advertising and also shows the mechanism of their impact on the target audience. The research material is social advertising, which is interpreted as a special type of persuasive metadiscourse integrating a persuasive intention with socially significant content. The aim of the study is to identify, systematize, and characterize linguistic indicators of persuasion in social advertising as a speech practice within the discourse of social harmony, as well as to determine their role in influencing the target audience and the cultural factors that determine their choice. Methods. Several methods were used to address the tasks, which were determined by the multi-level nature of the research object. The choice of methodology tools was determined by the need to combine macroanalysis of discursive practices with microanalysis of specific language means. The following methods were used: the method of language description, which served as the foundation for this study and was applied at all stages of the work; the method of conceptual modeling; the method of classification and typologization; the comparative (contrastive) method; the method of language‑stylistic analysis, aimed at identifying and describing specific language means of implementing persuasiveness; and the method of interpretive analysis. At the final stage of the work, the method of theoretical synthesis was applied, which made it possible to combine the results obtained at different levels of analysis into a comprehensive description of the functioning of persuasive linguistic indicators in the discourse of social harmony. Synthesis is carried out both in the horizontal dimension (generalization of data obtained using different methods) and in the vertical dimension (integration of theoretical concepts and empirical observations into general conclusions). Results. Two types of persuasive strategies are distinguished: persuasion, which appeals to the rational sphere of the addressee, and coaxing (a suggestive strategy), which is focused on emotional perception. Within each strategy, speech tactics are identified and characterized. Special attention is paid to the language means of realizing persuasiveness, that is persuasive indicators: inclusive constructions, appealing to the addressee, metadiscursive markers, indicators of social modality, means of positive politeness, as well as emotive vocabulary and implicatures. Conclusions. The conclusions emphasize that the system of persuasive indicators is multi‑level in nature. A typology of persuasive language indicators of social advertising is presented. A comparative analysis of social advertising in Russian, German and Italian reveals that the choice of persuasive means is culturally conditioned: Russian social advertising tends to use psycholinguistic techniques, German social advertising is characterised by rational argumentation, and Italian social advertising uses more playful strategies. In general, the effectiveness of social advertising in the discourse of social harmony directly depends on taking into account the cultural characteristics of the target audience.