This study examined the dynamic association between teacher–child relationship quality and Chinese toddlers' developmental functioning. The participants, located in Hong Kong, consisted of 82 Chinese toddlers and their teachers. With a two-wave longitudinal design, teachers rated the children's developmental functioning and their own relationships with each child. The results showed that the relations between teacher-child relationships and developmental functioning differed across aspects of child development. Specifically, teacher–child relationship quality predicted and was predicted by toddlers' comprehension and personal-social skills; teacher-child relationship quality predicted but was not predicted by motor and self-help skills; finally, expressive language skills predicted but were not predicted by teacher-child relationship quality. Follow-up analyses suggested that the observed relations operated similarly for boys and girls, but differently between younger and older age groups. We conclude by discussing the study's limitations and offering suggestions for promoting developmentally appropriate childcare experience for toddlers. Copyright © 2020 Elsevier Ltd. All rights reserved.