Introducing Nanoscience and Nanotechnology (NST) topics into school science curricula is considered useful for an in-depth understanding of the content, processes and nature of science and technology, and also for negotiating the social aspects of science. This study examines (a) the development of an inquiry-based Teaching–Learning Sequence (TLS) on NST topics, which incorporates socio-scientific issues and out-of-school learning environments and (b) the dissemination of the developed TLS through the training of further teachers. In both cases, a participatory design, in particular Communities of Learners (CoLs), was established, consisting of teachers, science researchers, science education researchers and science museum experts. As a theoretical framework for the TLS development, the Model of Educational Reconstruction is used. The qualitative analysis of the obtained data highlights that teachers’ interactions with colleagues in the CoL on issues regarding the educational reconstruction of the different aspects of the TLS impact the process of its development. Regarding the dissemination of the TLS, the findings indicate that teachers modified several elements of the TLS and particularly the included activities, influenced by their mentors’ prior experience and their own rich contextual knowledge. Finally, guidelines for the development and dissemination of a TLS are discussed.