Working memory (WM) underpins learning and is strongly associated with academic achievement. Children with poor WM need support in the classroom, but little is known about teachers’ understanding of WM. An online questionnaire (N = 1425) assessed educational professionals’ understanding of key concepts related to WM. Respondents generally showed some understanding, although most overestimated WM duration. There was also considerable variability in the signs identified as being associated with poor WM and possible strategies to assist such children. This demonstrates the need to provide teacher training about WM, and for collaboration between researchers and teachers in developing support materials.