Romantic jealousy describes a feeling when individuals suspect losing their romantic partner to a potential rival. Social media has a high potential to trigger romantic jealousy as it offers almost unlimited opportunities to build social relationships. Thus, it is unsurprising that many studies are now examining social media-induced jealousy (SoMJ). However, there has been a lack of standardized instruments that can capture SoMJ independently of a specific social media platform. In the present two studies, we developed the 9-item Digital Jealousy Scale (DJS) in German and English and examined its psychometric properties using three heterogeneous samples from Germany and the United Kingdom. The postulated one-factor structure fitted the data very well. Additionally, construct validity was established by showing the expected correlations between the DJS and personality variables such as other jealousy measures, attachment dimensions, self-esteem, and the Big Five dimensions. The DJS is thus a valuable instrument to assess SoMJ.