Working memory, ability to remember and manipulate information, is crucial to academic attainment. The aim of the present study was to understand teachers' perception of working memory and how it impacts on classroom behavior. A semi-structured interview was used to explore teachers' ability to define working memory, identify these difficulties in the classroom, and effectively support struggling students. Teachers were then asked to identify students in their classroom whom they felt exhibited troublesome behavior. The data indicated that teacher awareness of working memory was quite low, with the majority of them only able to correctly identify one or two signs of working memory failure and effective strategies to support it in the classroom. The study also found that students the teachers consider as troublesome showed signs of working memory failure. The practical implications for screening and supporting students who exhibit troublesome behaviour in the classroom are discussed.