Increasing numbers of social media users report being blackmailed on social media following their sharing of sensitive and personal information. However, little is known about this emerging crime and its victims. Using a survey of adult WhatsApp users in Oman (n = 1452) and interviews (n = 18) with victims and Omani criminal justice professionals, this study addresses this gap by examining the prevalence of blackmail among adult WhatsApp users arising from their voluntary self-disclosures, as well as the characteristics and vulnerabilities of those who fall victim to this activity. New insights are also offered into the factors influencing victim’s decisions to report their experiences to criminal justice professionals, as well as the challenges associated with investigating and prosecuting this activity.