Summary Public diplomacy's scholarship and practice are evolving and seeking to adapt to the expanding interests, expectations, connectivity and mobility of the publics that have come to define the field in an organic fashion. The characteristic distinction between international and domestic publics as the key to defining the practice of public diplomacy is increasingly challenged by public audiences that are no longer constrained by such traditional delineations. The attention on the involvement of domestic publics in public diplomacy, or its domestic dimension, has to be understood within this context. This article aims to cast further light on public diplomacy's domestic dimension, with Canada and Australia - two countries that have much in common - as the launch pads for discussion. The article's first section investigates the approach and development of public diplomacy's domestic dimension in both countries and draws out the similarities and differences. The second section identifies the opportunities, challenges and tendencies in its practice as well as the conceptual implications. The article finds that while differences in approach remain, Canada and Australia have more in common than not when it comes to involving domestic audiences in international policy, especially in recent years. Their practice of public diplomacy's domestic dimension appears to be resilient and adaptive in nature, although it has been subject to fluctuations resulting from changes in the political climate, leadership styles and governmental preferences, and resource availability. Additionally, reconceptualizing public diplomacy with a domestic dimension and constructivist underpinnings opens the window on norms that are taken for granted in diplomacy and offers the potential for a more inclusive view and practice - a better fit for its time.