This paper aims to report on the development of a rubric and formative assessment targeting pre-service teacher instructional planning in an English teacher education programme in Indonesia. Ten curriculum components as proposed by Van den Akker were incorporated to develop the rubric. Educational Design Research (EDR) as an approach was employed to guide this study. The findings suggest that the rubric is useful in the formative assessment of the pre-service teacher instructional planning. Teacher challenges in instructional planning were also found, particularly in the five aspects: writing good learning objectives, defining teacher roles, determining learning activities, assessing outcomes, and allocating times needed for learning activities. The rubric is also effective in assessing not only cognitive and psychomotor learning, but also affective/attitude learning. Finally, the rubric can also be used to assess the internal consistency of the instructional planning.