This study examined both the development of synchronisation activities and the way emotion affects these activities in children and adults. Children aged from 3 to 8 years, as well as adults, performed a spontaneous motor tempo (SMT) task and a synchronisation task with a 500-millisecond and 700-millisecond inter-stimulus interval (ISI), followed by a continuation task, in both an emotion-free and an emotional context (High-Arousal, Low-Arousal, and Neutral). The results showed that the SMT was faster and more variable in the younger children. In addition, the younger children found it more difficult to slow down their tapping rate in synchrony with the 700-millisecond ISI, with the result that they quickly returned to their internal tempo in the continuation phase. In contrast, the 8-year-olds' synchronisation performance was close to that of the adults. However, despite developmental changes in synchronisation skills, all the participants produced faster tempi in both the SMT and the synchronisation task for the High-Arousal emotion than for the other emotions. This suggests that emotions induce an automatic distortion of motor timing as has also been observed for the perception of time.