The current study examined whether individual differences in depressive and anxious symptoms relate to level of daily self-esteem and instability of daily self-esteem in adolescence. Participants were a racially and ethnically diverse sample of adolescents (79 girls, 65 boys; M age = 13.53 years). Adolescents reported on their depressive and anxious symptoms during a baseline home visit. Then, adolescents reported on their daily self-esteem over the course of 12 consecutive days. Using hierarchical linear modeling analyses, level of daily self-esteem was negatively associated with depressive but not anxious symptoms. In addition, a positive relation emerged between instability of daily self-esteem and depressive symptoms when controlling for level of self-esteem; a similar relation did not emerge for anxious symptoms. The differential findings that emerged between both level and instability of daily self-esteem and depressive versus anxious symptoms may be linked to differences in the temporal orientation of these two types of internalizing symptoms; specifically, depressive symptoms result from backward-looking rumination over previous experiences, whereas anxious symptoms emerge from forward-looking worry about future events (Wenze et al., 2012).