This research explores the types of questions teachers ask their students in CLIL classrooms and how they can optimize their use of these questions. It came about as a result of a slowdown detected in the learning capacity of students after the first two years of CLIL programmes in the region of Murcia, Spain. The first data collected demonstrated that most classroom interactions only involved responding to display questions, which required the mere remembering or understanding of concepts. Hence, we implemented a testing methodology to determine whether stimulating higher-order thinking would result in a significant improvement in student outcomes. The results showed that this methodological intervention succeeded in its aim, as a marked improvement in student responses was achieved. These findings highlight the value of optimizing the use of questions to foster critical thinking and empower students for the knowledge economy in which we live.