After examining several conceptual elements of peer-assisted learning and peer tutoring, this article presents a study analysing the effects of peer tutoring--with fixed and reciprocal roles--in the improvement of curricular competence of Catalan language skills, self-concept as a writer and satisfaction with pedagogical assistance. The results, using curricular competence improvement as a control, show an increase in self-concept as a writer for all students who were given the opportunity to act as tutors; either in fixed or in reciprocal role tutoring. Only fixed tutees, but not reciprocal tutees, feel more satisfied with their peer tutors than with the teacher's help. (Contains 4 tables.)