This paper is an attempt to provide a cognitive approach to question tags, as grammatical constructions that show different syntactic forms. We propose an account based on the following points: (i) definition of question tags, (ii) contrastive analysis of the structures in several languages (Catalan, Spanish, French, Italian, English and German), (iii) pragmatic approach to question tags, (iv) syntactic approach, and (v) study of question tags as grammatical constructions. Our main claim is that the various forms that they show in the languages considered are closely related, and that they evidenciate some of the three definitory characteristics of the construction, namely, its mixed modality between assertion and interrogation, on the one hand, and halfway between affirmation and negation, on the other, its relationship with the truth value of the proposition it follows and finally its subjective character, which is connected with the manifestation of the opinions and discoursive attitudes of the speaker