This article discusses how the concept of "good citizens" in Singapore is linked to the principle of harmony, characterised by collectivism and a strong interventionist government. The value of religious harmony is actively promoted by the Singapore government and supported by the religious leaders. This article argues that the principle of religious harmony helps to ensure that there are relative peace and tolerance among the various religious communities. But with religious revivalism and continual terrorist threats from some Islamist groups, it has become increasingly difficult for religious believers in Singapore to balance their national and religious identities, loyalties and duties. The on-going challenge for the Singapore government is to promote a conception of "good citizens" that takes into consideration the multiplicity and complexity of religion and citizenship.