This paper applies the theory of relational development to exam¬ine how the Islamic State of Iraq and al-Sham (ISIS) recruits new members. Relational development postulates that individuals follow relationship stages in order to reinforce their interpersonal communication or social bond. The relational development model includes five main stages, called the five stages of relationship escalation, or the “coming together” stages. These consist of initiating, experimenting, intensifying, integrating, and bonding. Overall, the authors of this analysis found that ISIS can success-fully recruit many people – particularly male and female youth – thanks to stage-by-stage relational development through internet chat rooms and social network sites (SNSs) like Twitter. By the same token, the authors also believe that, should ISIS not use internet chat rooms and social network sites (SNSs), and if ISIS were not following those stages of relationship es-calation, their recruitment process would not be as efficient.