Models of education delivering content teaching through learners' second language have rapidly increased in recent decades and are thought to offer a 'naturally' motivating context for learners to use and learn the medium of instruction (MoI). However, the relationship between MoI and language learning motivation (LLM) specifically is under-explored. In light of calls for contextually responsive theorizations of LLM, this study examines interactions between English language learning motivation (ELLM) and micro (MoI classrooms) and macro (schools) contexts in Hong Kong. ELLM measures were administered to Hong Kong secondary school learners of English (N = 3854), aged 11-14, studying in English, Chinese and Mixed mode of instruction schools. ANOVA results indicate higher levels of ELLM among EMI students on most measures and effects of MoI on three LLM constructs. The results support the relevance of a required orientation in explaining participants' ELLM and challenge the applicability of the ideal L2 self, which may be attributable to context rather than cultural difference. Implications are discussed for existing understandings of the MoI-LLM relationship, as well as discussions around culturally relevant theorizations of LLM.