The Western Balkans faces a double challenge from online extremism. Online platforms are facilitating the specific targeting of the region by diverse international extremist narratives. Meanwhile regional histories and geopolitics are being appropriated to justify extremist actions and narratives around the world. This is part of a wider trend that underscores the growing challenge posed by the proliferation of transnational extremist ideologies on online platforms, both violent jihadist and extreme right wing. In the Western Balkans, this poses a number of specific risks. While the issue of the prevention, mitigation, and regulation of online extremism is a global one, there are a number of region-specific considerations relevant to effective policy and practitioner responses.