This study examines a collaborative model of teaching English by native English-speaking teachers (NESTs) and local teachers in Taiwanese elementary schools. This co-teaching model (hereafter referred to as "the CT Model" or "the Model") is proposed by the author based on previous studies in this field as an attempt to improve the performance of teaching practice of this kind. Through multiple research methods, the author examines the utilization of the CT Model, the impact of the Model on the teachers and the elements of a viable co-teaching model. The study shows that the CT Model was considered well formulated, and the components included in the Model were necessary for co-teaching of English. After implementing the Model, the teachers became more aware of their teaching practice. The Model also served as a reminder for the teachers of what they could do when working with their co-teachers. The study indicates that the components of the Model were implemented differently by the teachers. Time constraints, which seem endemic to all teaching professionals, presented a challenge for the teachers when they attempted to work together by following the Model. Finally, implications for the development of plausible collaborative models of teaching English by NESTs and local teachers are discussed.