Rethymno (Greek: Περιφερειακή ενότητα Ρεθύμνου) is one of the four regional units of Crete, Greece.

These are (number as in the map in the infobox):[2] The Rethymno prefecture (Greek: Νομός Ρεθύμνου or Ρεθύμνης) was created while Crete was still an autonomous state, and was preserved after the island joined Greece in 1913.

As a part of the 2011 Kallikratis government reform, the Rethymno regional unit was created out of the former prefecture.

[2] Note: Provinces no longer hold any legal status in Greece.

The main towns of the regional unit Rethymno are (ranked by 2021 census population):