Advances in nanotechnology have drawn attention to nanotechnology education. The aim of this study is to determine awareness, exposure, and knowledge levels of science (physics, chemistry and biology) teachers about nanoscience and nanotechnology. Teachers (N=624) from secondary schools in Turkey comprised the working group. Descriptive methods were used in data analyses. Awareness and exposure subscales were adopted from the "Nanotechnology Awareness Instrument" developed by Dyehouse et al. (2008), and the knowledge subscale, developed by the authors, was added to the Turkish version. Differences among or between the teachers' awareness, exposure, and knowledge levels regarding nanoscience and nanotechnology were determined. No significant differences were found in levels of awareness, exposure, and knowledge of teachers in terms of subject specialisation and educational levels; however, some significant differences were found in gender, tenure, grade and type of school, in-service training participation, following scientific publications, documentary watching frequency and school localisation variables. In general, nanoscience and nanotechnology awareness, exposure, and knowledge levels of the teachers were at a "neutral" level. This study shows needs for further training of science teachers in nanoscience and nanotechnology, to increase their level of awareness and knowledge and to ensure their preparedness for teaching this topic.