Executing actions in a specific order is a critical component of many action sequences that children must acquire, the majority of which are learned through observation and imitation of others. Although a wealth of evidence indicates that children can process and represent temporal order in memory, relatively little is known about the development of this ability and the cognitive mechanisms that support it in the context of imitation. The present research investigated 4- through 8-year-old children's ability to learn the temporal order of novel, arbitrary action sequences via imitation. On Day 1, children observed and imitated four instances each for two different multistep sequences. One sequence was easy and the other was difficult, in terms of categorizing the items used in each instance. For one sequence, the experimenter also performed one instance in a deviant temporal order, which occurred either early or late in learning. Memory generalization for each sequence was assessed on Day 2. Results indicated significant effects of age and sequence difficulty on children's ability to recall the individual actions as well as the standard order. Experiencing the deviant order also uniquely disrupted children's ability to generalize the order. Experiencing the deviant early in learning globally lowered children's memory for both sequences. Thus, children's ability to learn temporal order develops slowly over childhood, is supported by foundational cognitive processes that operate in a hierarchical fashion, and is highly sensitive to variable temporal input. These results have implications for theories of imitation and cultural learning more broadly.