Teaching English in elementary schools has been an important educational policy in Asian countries over the past several decades. This study investigates how in-service teachers in elementary schools conceptualize their practical knowledge about English teaching in Taiwan. It provides examples of experiences and practical knowledge that English teachers have developed in their own contexts. The practical knowledge of teachers was investigated using a qualitative case study. Three in-service teachers participated in this study. Data include interviews, classroom observations, teachers' reflective journals, and teaching materials. The study provides practical principles and rules of practice for elementary EFL teachers. It offers insights that policy makers need to consider in setting up a sound English teaching and learning program for elementary schools in EFL contexts. (Contains 1 table.)