The big-fish–little-pond effect (BFLPE) postulates that class-average achievement has a negative effect on
students' academic self-concept. We hypothesized that teachers' use of differentiated instruction strategies
would attenuate the BFLPE on French self-concept (FSC). We also explored whether this moderation effect
depended on children's individual achievement (i.e., a three-way interaction among class-average achievement,
individual achievement, and differentiated instruction). Using hierarchical linear modeling, we tested this
moderation effect in a sample of 422 elementary students nested in 27 classrooms. The results showed that
the three-way interaction was significant. Simple slopes indicated a significant BFLPE only for students with
low individual achievement and for whom teachers reported less frequent use of differentiated instruction
strategies. Our findings provide insights into which students may be the most affected by the BFLPE and which
teaching practices can attenuate its negative consequences on students' FSC. We discuss results in relation to
the literature on the BFLPE and on differentiated instruction