This resarch note examines the ways in which Islamic State supporters on Telegram, an encrypted messaging app, renegotiate gender boundaries. The introduction positions receptions of female ISIS accounts in the online space within the context of the roles that women are expected to fill and ISIS’s tentative acceptance of women fighting on the battlefield. An overview of Telegram gender social norms is provided before discussing the methodology used to gather supporting archival data to analyze the renegotiation of gender boundaries on Telegram. This section is followed by an analysis of a case study that considers the wider implications of what this says about women’s agency and involvement in terrorist groups online. The conclusion addresses the policy implications of possible shifts in gender social norms and the shape that women’s engagement in violent jihadist groups might take in the future.