In the present study, we examined the extent to which the responses of teachers and mothers toward a particular child are similar in respect to their instructional support and affect, and whether child characteristics predict these responses. The data of 373 Finnish child-teacher-mother triads (178 girls, 195 boys) were analysed. Teachers and mothers reported their instructional support and affective responses toward a child in the school/homework context in Grades 1, 2, 3, and 4. At the beginning of Grade 1, the children’s performance in reading and math was tested, and teachers evaluated the children’s externalizing and internalizing problem behaviour. The results demonstrated that mothers and teachers showed similar instructional support and affective responses toward a particular child at the end of Grade 1. Moreover, children’s poor performance in reading and math at the beginning of Grade 1 was associated with high amounts of both teachers’ and mothers’ instructional support at the end of Grade 1, while children’s externalizing problem behaviour was strongly related particularly to teachers’ but also to mothers’ negative affective responses at the end of Grade 1. The results provide evidence for the evocative impact of child characteristics on the child’s interpersonal environment at the start of child’s school career.