This short-term longitudinal study investigated the simultaneous influences of adults’ (mothers and teachers) educational expectations and youth’s achievement (standardized test scores and teachers’ ratings of academic performance) across a 3-year time span on youth’s performance in school (GPA). Participants were an ethnically diverse sample of 426 low-income urban youth, ages 6 through 16 at T1. Results from cross-lagged and autoregressive path analyses indicated stability in adults’ expectations and youth’s standardized test scores; cross-lagged influences of teachers’, but not mothers’, expectations across time; and effects of youth’s achievement outcomes on adults’ expectations at T2, but not vice versa. Overall, the pattern of findings demonstrate that adults’ educational expectations are dynamic and responsive to how youth are faring in school and to changes in academic performance across time.