Chinese as the medium of instruction (MOI) is used across the curriculum for early childhood education in Hong Kong; however, kindergartens with non-Chinese speaking (NCS) students adopt different MOI, in which English remains an integral part of learning and teaching, to cater to the needs of NCS students and their families. The present study investigated how different modes of MOI adopted in six local kindergartens affected the Chinese language learning of 457 NCS students. Effective Chinese learning of the NCS students in their first year of kindergarten schooling and its relation to their Chinese language proficiency were examined. The preliminary findings showed that the Chinese MOI was relatively effective in enhancing NCS students' learning Chinese in comparison to English and dual-language MOI. Deliberate considerations on different contexts of kindergartens of varying proportions of NCS students for Chinese language learning is essential whilst the choice of MOI remains school-based, particularly in aspects of enhancing NCS students' Chinese language proficiency for their smooth Primary One transition and earlier social integration.