Eucratideia was an ancient town in Bactria mentioned by a few ancient writers. It was most likely a foundation of Eucratides I who is the more important ruler of the Greco-Bactrian Kingdom with the name Eucratides. Not much is known about this city and it might be just a renaming of an already existing town rather than a new foundation. Renaming of cities was a common practise in the ancient world.
The location of Eucratideia is disputed. Some proposed locations are:
- Dilbarjin 
- Qarshi; the 1923 work "The Encyclopaedia Metropolitana: Or Universal Dictionary of Knowledge" states: "Eucratidia, named from its ruler, (Strabo, xi. p. 516.) was, according to Ptolemy, 2° North and 1° West of Bactra." As these coordinates are relative to, and close to, Bactra, it is reasonable to disregard the imprecision in Ptolemy's coordinates and accept them without adjustment. If the coordinates for Bactra are taken to be , then the coordinates can be seen to be close to the modern day city of Qarshi.