This chapter examines and assesses Na Fianna Éireann’s military contribution to the Irish Revolution during the years between the establishment of the Irish Volunteers in 1913 and the end of the Irish Civil War in 1923. It identifies and discusses the Fianna’s performance of various military functions or tasks, illustrating each with examples from different events of the Irish Revolution. It contrasts young Fianna activists in the early twentieth century with the child soldiers of more recent years, noting that Fianna members chose to be militarily active, tended to be adolescents and were not likely to perform combat roles until they were in their later teens or early twenties. The chapter also highlights the personal price paid by Fianna members for their activism and considers how the Fianna’s military contribution to the Irish Revolution was recognised by the Irish state and others in subsequent years.