This study was an attempt to examine the relationship between anticipatory looking reactions treated as an index of implicit mental competence and the development of syntax and executive function. In a study with fifty-eight 3- to 5-year-olds there were used eye gaze and verbal measures of false belief understanding, tasks on complement and embedded clause syntax (EmCS), inhibitory control and working memory. Controlling for age and other language and executive measures EmCS accounted for a small but significant amount of variance in looking reactions. When data of children who gave correct verbal answers were discarded there was no an independent of age link between looking reactions and EmCS. The results suggest the separateness of the mechanisms of implicit and explicit mental competence, but some connections between implicit competence and syntax may result from the penetration of an explicit mental competence into looking reactions.