Mental health research demonstrates that children with conduct problems (CP) and callous-unemotional (CU) traits differ in important ways from children with CP alone, including differences in primary caregiver attachment quality. This research suggests CU may also influence the quality of attachment between children with CP and their teachers. This study compared children with CP alone (CP), CU alone (CU), both CP and CU (CPCU), and neither CP nor CU (comparison) on measures of the student--teacher relationship (STR). Participants were 1,554 students from seven elementary schools. Teachers completed ratings of STR, behavior (CP, CU, attention-deficit/hyperactivity disorder [ADHD]), and impairment approximately 4 to 6 weeks after the start of the school year, and again 4 to 6 weeks before the school year's end. Random intercept hierarchical linear models (HLMs) showed that (a) children with CPCU had the highest conflict and lowest closeness with teachers at the start of the school year and the greatest end-of-Stuyear impairment, (b) higher conflict and lower closeness with teachers at the school year's start were associated with greater end-of-the-year impairment, (c) there was no interaction between group (CP, CU, CPCU, or comparison) and STR in predicting end-of-the-year outcomes, and (d) ADHD was robustly associated with end-of-the-year impairment.