This work aims to study the role of the vocabulary and the syntax of complementation on a specific aspect of the Theory of Mind: children’s ability to distinguish between real and pretend emotions. A total of 70 children (37 aged four years; 33 aged six years) were individually administered the following tasks: a sentential complement sentences task, a task of understanding pretend actions, two tasks of understanding pretend emotions (in oneself and in others), and a receptive vocabulary test. The results showed significant correlations between the ability to understand pretend emotions and both the vocabulary and the syntax of complementation, but only in four-year-olds. Though pretend emotion understanding was found to be more tied to syntax of complementation than to vocabulary, this type of syntax was not a necessary or a sufficient condition to understand pretend emotions. The results are discussed in the light of the importance of the links between language and emotion understanding.