Gendered occupational and educational choices have often been traced back to gender differences in students’ domain-specific ability self-concept and intrinsic motivation. This study explored the role of believing in an “innate” math or language arts ability (i.e., having a fixed mindset) for gender differences in students’ ability self-concept and intrinsic motivation in 423 female (49%) and 447 male (51%) tenth graders from Germany (age M = 16.09 years, SD = 0.68, range: 14–18 years). In line with math-male stereotypes, believing in “innate” math ability was associated with lower ability self-concept and intrinsic motivation in female but not male students. In language arts, students’ mindsets were unrelated to their motivation. The results suggest that a fixed mindset presents an additional burden for female students in math, but not for male or female students in language arts