Introduction: Against the background of contradictory research findings in the field the present study aimed at unraveling the structural complexities of gender differences in secondary students' verbal self-concepts and, thus, analyzing possible gender x achievement interaction effects in the L1 German and L2 English language subject. According to an internal distress perspective significantly depressed self-concept scores for the female learners, in particular, at the low achievement level were assumed. Method: Data were gathered in a sample of 256 ninth grade students from German inner-city grammar schools. For measuring students' L1 and L2 self-concept two subject-specific scales were administered. For measuring their achievement in each language subject teacher competence ratings as well as (self-reported) marks were used. With respect to the L1 German language subject, only a significant main effect of the achievement variable was found. Neither a gender effect nor an achievement gender interaction could be demonstrated. Therefore, interindividually existing self-concept differences in favor of the female learners appeared to largely reflect their better achievement in the native language subject. Results: With respect to the L2 language subject, a significant interaction effect between the achievement and gender variable occurred. Within the low achieving subgroup the female learners displayed substantially lower self-concept scores than their male counterparts--at least concerning the latest mark criterion. Hence, they more strongly suffered from internal distress. Discussion: Especially in the L2 English language subject a gender x achievement effect could significantly explain differences in the learners' self-concept. Consequently, these differences cannot be merely ascribed to a gendered view of language subjects--which commonly favors the female learners. Gender stereotyping effects will operate in a more complex manner. In particular, they appear to affect the students' self-concept not primarily as a matter of subject rather as a matter of cognitive-motivational processing in the case of individually cumulated failure experiences--thus evidently unfavoring the female learners. However, the findings considerably differed across both the L1 and the L2 language subject and, thus, still need further clarification.