The primary aim of the present study was to examine the way in which instructional and emotional aspects of teacher support combined to predict children's engagement in learning-related activities in kindergarten classrooms that served a socio-economically diverse population of children. Observations were conducted on teachers and children in 45 classrooms. Results revealed that instructional and emotional support in combination were predictive of the intensity of children's learning engagement. The effect of instructional practices was contingent on the emotional tone of the classroom. The instructional practices had larger effects on the mean level of engagement in classrooms with more positive emotional tone. The study has critical implications for future research in terms of classroom environments supporting children's learning.