In the aftermath of the Second World War, when the Cold War and independence from European colonies were eminent, international radio broadcasting became the contested domain of nationalist leaders, advocates of internationalism, colonial authorities, and ordinary listeners over the meaning of self-determination. The paper asks how Moroccan nationalist leaders in the last few years before the independence (1956) faced this new media, utilized it as their weapon against the colonizer, and simultaneously established their claim as the voice of their people. By analyzing primary written and audio materials from the speeches given by the Moroccan nationalist leaders on the radio program Ṣawt al-‘Arab (Voice of the Arabs) of Radio Cairo, a key Pan-Arabism radio broadcasting supported by the revolutionary Egyptian regime, as well as the French intelligence reports, the paper studies what these Moroccan leaders spoke behind the microphone, how ordinary citizens in French colonial North Africa listened to these voices afar, and how the French colonial authorities monitored the emerging novel media of the mid-twentieth century. According to research findings, the paper argues that international radio broadcasts from Cairo provided a platform for Moroccan nationalists to appeal to the broader Arab regional audience, connecting their aspiration for independence and the momentum of Pan-Arabism. Moreover, the utilization of radio allowed ‘Allāl al-Fāsī, an exiled leader of the Istiqlal Party, to reinforce his own position as a popular nationalist leader. Indeed, in comparison with other existing media, radio was able to convey voices directly to the populace by arousing listeners’ emotions more effectively and transcending gender spatial boundaries. The fact that the French colonial authorities were so keen on surveilling and counteracting the anti-colonial propaganda disseminated on air from outside of their proper colonial domain attests to the impact radio broadcasting had on the nationalist struggle. The paper manifests the importance of intimate relations between establishing political authority and mastering the media. In particular, the international radio broadcasting that appeared at the onset of remaking of the international order amidst the Cold War provides significant insights on the interactions of internationalism and postcolonial state-making, through the lived voices from the past.