Where courses have as an aim the promotion of reflective practice, it will enhance the achievement of the goal if the level of reflective thinking is assessed. To do this in a satisfactory way requires a reliable protocol for assessing the level of reflection in written work. This article presents a protocol that can be used to guide the allocation of work to four categories, namely: habitual action/non-reflection, understanding, reflection, and critical reflection. Intermediate categories can also be used. Detailed descriptors of each category to guide the process are provided. The protocol was tested by four assessors independently using it to grade a set of written work, and very good agreement was obtained.