The ‘unwilling or unable’ doctrine is a controversial concept in the international law on the use of force. Under this doctrine, a victim state may engage in lawful extra-territorial self-defence when the host state is unwilling and/or unable to mitigate or suppress the threat posed by domestic non-state armed groups (“NSAGs”) in its territory. The ‘unwilling or unable’ doctrine is increasingly referred to by States accusing other States of “being unable to prevent terrorist groups from using their territories as ‘safe havens’ for launching attacks against the intervening states.” However, it is not (yet) law. Many States, particularly those in the Global South, have contested the doctrine as rewriting or reinterpreting the law of self-defence. This paper analyses the law on self-defence as it stands, the rise of the unwilling or unable doctrine, State practice regarding its use, and the ways in which Pakistan has been a victim to the doctrine by the US and India, but has also seemingly engaged in it problematically in Afghanistan. The article also proposes a way forward in which States in the Global South remain clear in their approach to this doctrine and not allow powerful, Western States from being able to violate their territorial integrity and sovereignty under the guise of self-defence.