This article presents an overview of the ecosystem of citizen science development in Lithuania and its potential to address United Nations sustainable development goals (SDGs). As citizen science is still in the early development stage in Lithuania, this case study is an example of ecosystem analysis in the period of early citizen science adoption. This article highlights the holistic analysis of the different components of this ecosystem, focusing on the three major dimensions at different levels—content, actors and processes. A conceptual model for the analysis of the citizen science ecosystem was developed based on the theoretical assumptions of Systems Theory and Service Science. The model was tested with empirical data. The empirical findings are based on 30 interviews with representatives of different stakeholder groups. Summarizing the analysis of the citizen science ecosystem in Lithuania and its potential for SDGs achievement, it can be stated that the first signs of a co-creative processes in the citizen science ecosystem have already emerged. Currently, in Lithuania, the main potential of citizen science concentrates on contributing to Goal #15: Life on Land, with some potential also for contributing to Goals #4, #10 and #11 and others. However, in order to use citizen science for addressing SDGs more comprehensively, there is a need for greater involvement of different stakeholders in citizen science, both in promoting citizen science activities and in ensuring data quality and that these activities are implemented in accordance with research ethics.