As a result of globalization of markets and increasing marine traffic, more than 130 introduced species have so far been recorded in the Wadden Sea. This unique coastal area constitutes an ecosystem of global importance and is recognized by UNESCO as a Natural World Heritage site. Efforts are made to monitor introduced species and to study their ecological effects on native species and biodiversity, ecosystem processes, and functioning. Social aspects that relate introduced species specifically to people and human society, however, are less studied. To explore this rather new field of research, qualitative interviews were conducted with stakeholders of the Wadden Sea, asking (1) How do introduced species affect people’s lives and (2) How do people perceive introduced species? The interviews were evaluated with a qualitative content analysis. As one first result of this exploratory study it turned out that immaterial aspects of the Wadden Sea, such as recreational potential and cultural identity, appear to be largely affected by introduced species. Moreover, the mere fact of change was mostly regarded with skepticism or aversion, regardless of actual effects. Based on the stakeholder interviews, a conceptual framework with the factors identified as influencing perception was developed. It is suggested that a better understanding of the social component is essential for an integrated management and sustainable solutions.