Recent development in trilingualism and trilingual education in minority dominated regions in China has highlighted the importance of training qualified trilingual teachers to support the students to achieve additive trilingualism. While research has been carried out in the domains of policy studies, trilingual education models and practice across China in general, there has been relatively little research on trilingual teacher training, especially remote western regions such as Xinjiang Uygur Autonomous Region (XUAR). Adopting a case study approach, this research evaluates the English language teacher training programmes, in order to identify issues and effective models for English language teacher training, and discusses them in the light of wider pedagogical implications for trilingualism and trilingual teacher training in China. This research adopted a multi-methods approach, in which the data were collected through survey questionnaires and interviews among the key stakeholders involved in the training programme, and further complemented by data through classroom observations. This study found that while no one seemed to disagree that Mandarin Chinese as the national official language but the second language (L2) for minority students is, and should be, strongly promoted because of its importance in every aspect of education in XUAR, it could also be the bottleneck and barrier which minority students face in learning English (their L3). This is due to the fact that many minority student trainees came to the university with a rather weak L2 which was nonetheless used as the medium of instruction for all subject teaching. The participating key stakeholders showed, on the whole, positive attitudes towards trilingual language teacher training. However, awareness of the importance of the minority language (their L1) during their trilingual language training needs to be raised, and its relationship with Mandarin Chinese and English during the trilingual teacher training process needs to be properly addressed. The research incorporates the results of the current research and theoretical perspectives regarding the nature of additive trilingualism and inclusive practice. In particular, the study proposes that the notion of English language teacher training should be trilingual teacher training in minority-dominated regions of China. As the notion of trilingual teacher training suggests, all three languages should be taken into account in designing the curriculum for English language teacher training. Appropriate incorporation of L1 and L2 into the curriculum would not only enhance their bilingual competence in their home language and Mandarin Chinese, but also facilitate their learning of L3, English. Finally, recommendations are made for trilingual teacher training and limitations are also acknowledged.