This study adds to the current literature on ongoing in-house professional development for teachers by exploring how administrators, other faculty, and the English-language (EFL) teachers who participated in Cambridge University Press’s Train the Trainer course (TTT) at King Abdulaziz University (KAU), Saudi Arabia, judged the TTT’s usefulness. To determine whether to support the TTT in the future, KAU wanted to identify how well its TTT graduates could provide professional development to their colleagues. This study’s aim is to discuss how positively those who were involved in the TTT, particularly the administration, the TTT graduate trainers themselves, and the other teachers who attended the workshops presented by first-year graduates of the ELI’s TTT responded to the course. The main question it addresses is how successful the implementation of such a TTT course can be at the English language institute of a Saudi university, like at KAU, so as to determine if the TTT should continue to be offered at KAU and more generally, taking the example of the ELI at KAU, if the TTT course should also be proposed at other English language institutes in Saudi Arabia. This study employed a Likert scale survey, semi-structured interviews, and open-ended questions with TTT participants, administrators, and other faculty to assess the TTT’s initial value. The main finding of this study is that so far, the TTT course was perceived as beneficial. However, future analyses should evaluate the longer-term effects of the TTT on teaching approaches and student learning.