This paper tries to determine whether there is a relationship between the mastery of LSQ (langue des signes québéoise ‘Quebec Sign Language’) and written French, acquired respectively as L1 and L2 by Deaf children educated bilingually. More precisely, it evaluates reading comprehension in French and mastery of space in LSQ. Indeed, the use of space in that language is hypothesized to be an appropriate indicator of global competence because it is not only involved in all forms of co-indexation but also is the means by which the language establishes relations between lexical elements. Reading comprehension is evaluated through the ability to locate and infer information in a text. Statistical analysis (Spearman correlations) shows that mastery of LSQ is related to reading comprehension.