Although there has been very little research on L3 motivation, it would appear that the gender divergences commonly found in L2 motivation are also apparent when a third foreign language is learnt. In a previous analysis of quantitative data Henry (2010a) found an inverse relationship between i) the extent to which students compared the L3-speaking/using self-concept with the L2 English-speaking/using self-concept, and ii) L3 motivation. Further, this effect was stronger for boys. In an attempt to shed light on these gender differences, interview data from students with differing motivational profiles were analysed using the theoretical framework of the working self-concept (Markus & Nurius, 1986; Markus & Kunda, 1986). The results suggest that, for these students, the L2 English self-concept is frequently invoked in L3 learning situations and that it has a referential function. Whilst the girls interviewed appeared to be able to offset the impact of L2 English by creating cognitive barriers and recruiting positive L3-related self-knowledge, the boys seemed to rely more on forms of self-knowledge that emphasize a capacity for hard work and determination. For some of the boys the pervasive impact of L2 English meant however that it was impossible to sustain a viable L3 self-concept.