<p>Songbirds like Ashy Prinia (<i>Prinia socialis</i>) actively defend their territories from competitors, intruders, or rivals, this study investigated the behavioural response of Ashy Prinias to conspecific song playback, focusing on their ability to differentiate between familiar neighbours and unfamiliar strangers. Conducted during the breeding season of 2023 in a suburban area of Uttarakhand, India, we employed a playback experiment using dummy models that mimicked conspecifics in their habitat. Two categories of songs were selected for playback: songs from neighbouring males of the focal males, and songs from randomly chosen strangers During both playback modes (neighbour songs and stranger songs), a range of behavioural parameters (song rate, territorial aggression, approach distance, vocalisation frequency) were documented. This comprehensive assessment aimed to understand the capability of an individual’s familiarity based on acoustic cues. Our research indicates that the Ashy Prinia's territorial behaviour was notably impacted by the presence of playback songs. Specifically, prinias exposed to the dummy model with playback song of stranger showed higher territorial aggression to defend the nest and territory, this aggressive response was characterized by an increased song rate and reduced approach distances compared to those exposed to the playback of neighbouring individual. The results strongly suggest that acoustic cues, particularly conspecific songs, are vital in shaping the territorial, communicative, and defensive behaviours of Ashy Prinia. This field study highlights the significance of a rival's song in triggering a heightened territorial defence behaviour in this tropical avian species native to the Indian subcontinent., demonstrating their ability to discriminate the neighbour – stranger vocal communication.</p>