Self-concept differentiation (SCD) has been of interest to researchers, mainly as a structural concept indicative of social specialization or self-concept fragmentation. Nevertheless, this aspect of self-representation has not been studied in regard to sexuality and the extent to which the sexual self may vary across different roles or situations. With the emergence of the Internet, people found new opportunities to explore and express aspects of their sexuality in multiple online scenes, thus increasing the complexity of human sexual experience and expanding the reach of sexual identity. The aim of this study is to investigate SCD in relation to the sexual self-concept, as experienced in the online and offline environments, and its effects on sexual identity, sexual satisfaction and online sexual behaviors. Data analysis pointed towards a fragmented self-view with high degrees of differentiation between the online and offline sexual self-instances being linked to a weaker sense of sexual identity, less sexual satisfaction in real life and less partnered online interactions. However, there were some indications that these relationships were influenced by how people perceive themselves sexually in one instance compared to the other. The results obtained in this study encourage further research on SCD as an important factor in understanding the real-world consequences of online sexual expression.