As children’s language abilities develop, so may their use of co-speech gesture. We tested this hypothesis by studying oral narratives produced by French children and adults. One hundred and twenty-two participants, divided into three age groups (6years old, 10years old and adults), were asked to watch a Tom and Jerry cartoon and then tell the story to the experimenter. All narratives were videotaped, and subsequently transcribed and annotated for language and gesture using the ELAN software. The results showed a strong effect of age on language complexity, discourse construction and gesture. The age effect was only partly related to the length of the narratives, as adults produced shorter narratives than 10-year-olds. The study thus confirms that co-speech gestures develop with age in the context of narrative activity and plays a crucial role in discourse cohesion and the framing of verbal utterances. This developmental shift towards more complex narratives through both words and gestures is discussed in terms of its theoretical implications in the study of gesture and discourse development.