Courtenay is Professor of Developmental Disorders of Language and Communication and the Vice Dean for Research in the Faculty of Brain Sciences at UCL. She is a Fellow of the Royal College of Speech and Language Therapists and a visiting Professor at the Department of Special Needs Education at the University of Oslo. She obtained her PhD in Experimental Psychology at the University of Oxford, working with Professor Dorothy Bishop on the overlapping language profiles that characterise autism and developmental language disorder.

Her current research focuses on language profiles across different developmental conditions and how language interacts with other aspects of social and cognitive development, particularly mental health. She led SCALES, a population study of language development and disorder from school entry to adolescence. She is also a founding member of the RADLD
campaign (https://radld.org/).