Abstract Studies of temperament from early childhood to adulthood have demonstrated inverse relationships between negative affectivity and effortful control. Effortful control is also positively related to the development of conscience and appears as a protective factor in the development of behavior disorders. In this study, the development of attentional mechanisms underlying effortful control was investigated in 2- to 3-year-old children, as indexed by their performance in a) making anticipatory eye movements to ambiguous locations and b) resolving conflict between location and identity in a spatial conflict task. The ability to make anticipatory eye movements to ambiguous locations within a sequence was clearly present at 24 months. By 30 months, children could also successfully perform a spatial conflict task that introduced conflict between identity and location, and at that age, children's success on ambiguous anticipatory eye movements was related to lower interference from conflict in the spatial conflict task. Children's performance on the eye-movement task was correlated with performance and reaction time on spatial tasks, and both were related to aspects of effortful control and negative affect as measured in children's parent-reported temperament.