Participants were 443 (52.6% male, 47.4% female) ethnically diverse, 1st-grade, lower achieving readers attending 1 of 3 school districts in Texas. Using latent variable structural equation modeling, the authors tested a theoretical model positing that (a) the quality of teachers' relationships with students and their parents mediates the associations between children's background characteristics and teacher-rated classroom engagement and that (b) child classroom engagement, in turn, mediates the associations between student-teacher and parent-teacher relatedness and child achievement the following year. The hypothesized model provided a good fit to the data. African American children and their parents, relative to Hispanic and Caucasian children and their parents, had less supportive relationships with teachers. These differences in relatedness may be implicated in African American children's lower achievement trajectories in the early grades. Implications of these findings for teacher preparation are discussed.