For teaching English to speakers of other languages (ESOL) to be seen as having substantial impact, learning that occurs in the classroom must transfer to situations outside the classroom. Unfortunately, education research shows that transfer can be difficult to promote. Therefore, ESOL teachers may want to ensure that their classes are as conducive as possible to transfer. In the many ESOL contexts in which textbooks play a central role in classes, this will mean ensuring that the textbooks used help as much as possible to promote transfer. However, evaluating the potential of ESOL textbooks to help promote transfer may not be straightforward with existing published resources. Therefore, this article describes and demonstrates a new textbook evaluation tool that was designed based on key ideas in scholarly work on learning transfer and patterns in current ESOL textbooks. The aim is to provide a practical tool that teachers can use to evaluate the potential of ESOL textbooks to promote learning transfer.