The paper explores the phraseological features of the Spanish language as a reflection of the culture and mentality of the people. The aim of the research is to determine the linguocultural features of Spanish phraseological units with the meaning “intelligence – stupidity/madness”. The authors emphasize the importance of studying the national and cultural component of the Spanish language, which is especially vividly and accurately reflected in phraseology. The scientific novelty of the research lies in the fact that Spanish phraseological units expressing different cognitive and mental states of a person are considered in a single context of the semantic opposition “intelligence – stupidity/madness”. Within the framework of the research, the phraseological units under consideration have been classified for the first time according to their components into the semantic spheres “Person”, “Animal world”, “Plant life”, “Objects”. Lexical differences in phraseological units of different variants of the Spanish language are also revealed. The results of analysing the components of phraseological units inherent in various national variants of the Spanish language determine the specifics of the verbalization of mental states and cognitive processes, taking into account the cultural characteristics of Spanish-speaking regions.