A growing number of toddlers are attending childcare institutions as part of China's establishment of its infant-toddler childcare service system. However, there is limited empirical evidence available regarding the quality of these childcare services. The purpose of this study is to investigate the quality of teacher - child interactions in Chinese toddler classrooms. Eighty-eight childcare institutions were assessed using the Classroom Assessment Scoring System, Toddler Version (CLASS -- Toddler). The findings indicated that, on average, teacher - child interactions were rated as being of moderate quality. The Emotional and Behavioral Support (EBS) domain scored higher quality levels compared to the Engaged Support for Learning (ESL) domain. Multilevel models revealed significant variations in teacher - child interactions across different types of activities. Free play activities demonstrated the highest EBS quality, while whole-group activities ranked the highest in terms of the ESL quality. Moreover, the children-to-teacher ratio was found to predict both the EBS and ESL quality, whereas group size was only associated with the EBS quality. The results from this study have important implications for future research and professional development of Chinese toddler teachers.