Lake Léman (Lake Geneva), Switzerland, is known to have undergone major environmental change over the last few decades, including changes in the abundance, distribution, and species composition of macrophytic plants (aquatic plants). In this study, questionnaires and key informant interviews were used to assess lake users’ perceptions of broad scale environmental change in the lake paying special attention tochanges in the abundance of aquatic plants and the perceived ecosystem services (ES) and ecosystem disservices (EDS) associated with them. In addition, we assessed whether users’ perceptions of aquatic plants had an impact on perceived management need. Most respondents (63%) perceived aquatic plant abundance to have increased over the last 10 years, primarily because of climate change. Aquatic plants were seen to benefit water quality through improved regulation and supporting services, and to provide important habitat and food for fauna. Most EDS associated with increased aquatic plant abundance were categorized as cultural or economic. User perceptions of the ES and EDS associated with aquatic plants affected support for management (60% of respondents supported some form of management), and such information is important for informing environmental decision making.