The behavioural phenotype of women with Turner syndrome (X–monosomy, 45,X) is poorly understood, but includes reports of some social development anomalies. With this in mind, accuracy of direction of gaze detection was investigated in women with Turner syndrome. Two simple experimental tasks were used to test the prediction that the ability to ascertain gaze direction from face photographs showing small lateral angular gaze deviations would be impaired in this syndrome, compared with a control population of men and women. The prediction was confirmed and was found to affect both the detection of egocentric gaze from the eyes (‘is the face looking at me?’) and the detection of allocentric gaze, where the eyes in a photographed face inspected one of a number of locations of attention (‘where is she looking?’). We suggest that dosage–sensitive X–linked genes contribute to the development of gaze–monitoring abilities.