Learning a third language (TL) brings with it particular pedagogical demands. In the pedagogy of TL learning now emerging, the development of students' metalinguistic and crosslinguistic awareness is of central importance. In particular, emphasis is placed on the benefits of cross-referencing with supporter languages. While comparisons with supporter languages have been shown to facilitate L3 production, recent research suggests that cross-referencing with the L2 may be detrimental to motivation. In the current study, 21 students learning L2 English and L3 German or Spanish were interviewed about comparisons involving L3 and L2 self-concepts. Results revealed that nearly all of the students were aware of making such comparisons. A number, however, had developed strategies to counteract the potentially detrimental effect that comparisons with the L2-speaking/using self-concept can have on L3 motivation. It is argued here that in emerging pedagogies of L3 learning proper account needs to be taken of cognitive and affective individual difference factors. In particular, as a means of offsetting the negative impact that a high-status supporter language can have on the learner's L3 self-concept, students should be made aware of the problem and helped to develop and make use of counteracting strategies.