The evolution of Information and Communication Technologies (ICT) has changed the way we communicate. Access to the Internet and social networks has even changed the way we organise ourselves socially. Despite advances in this field, research on the use of social networks in political discourse and citizens’ perceptions of public policy remains scarce. So, the empirical study of politicians’ discourse on social networks in relation to citizens’ perception of public and fiscal policies according to their political affinity is of particular interest. The aim of the research is, therefore, to analyse positioning, from a dual perspective. Firstly, the study analyses the positioning in the discourse of the communication campaigns posted on social networks of Spain’s most prominent politicians. And secondly, it evaluates whether this positioning is reflected in citizens’ opinions about the public and fiscal policies being implemented in Spain. To this end, a qualitative semantic analysis and a positioning map is performed on a total of 1553 tweets published between 1 June and 31 July 2021 by the leaders of the top ten Spanish political parties. In parallel, a cross-sectional quantitative analysis is carried out, also through positioning analysis, based on the database of the Public Opinion and Fiscal Policy Survey of July 2021 by the Sociological Research Centre (CIS), whose sample is 2849 Spanish citizens. The results show a significant difference in the discourse of political leaders’ social network posts—which is more pronounced between right-wing and left-wing parties—and only some differences in citizens’ perception of public policies according to their political affinity. This work contributes to identifying the differentiation and positioning of the main parties and helps to guide the discourse of their posts.