Dionysos (Greek: Διόνυσος) is a northern suburb of the Athens agglomeration and a municipality in northeastern Attica, Greece.

Its built-up area is continuous with those of the neighbouring suburbs Drosia and Rodopoli to the northwest.

Even though the town is located only 20 Kilometres away from central Athens, it has a completely different climate, with weather being significantly cooler, including frequent snowfall during the winter.

The A1 motorway (Athens–Thessaloniki–Evzonoi) and the railway from Athens to Thessaloniki pass through the western part of the municipality, near Agios Stefanos.

The public library of Dionysos is located in the town hall, includes over 3500 books available to registered residents to borrow for free.