The Edict on Maximum Prices (Latin: Edictum de Pretiis Rerum Venalium, "Edict Concerning the Sale Price of Goods"; also known as the Edict on Prices or the Edict of Diocletian) was issued in 301 AD by Diocletian. The document denounces monopolists and sets maximum prices and wages for all important articles and services.

The Edict exists only in fragments found mainly in the eastern part of the empire, where Diocletian ruled. The reconstructed fragments have been sufficient to estimate many prices for goods and services for historical economists (although the Edict attempts to set maximum prices, not fixed ones). It was probably issued from Antioch or Alexandria and was set up in inscriptions in Greek and Latin.

The Edict on Maximum Prices is still the longest surviving piece of legislation from the period of the Tetrarchy. The Edict was criticized by Lactantius, a rhetorician from Nicomedia, who blamed the emperors for the inflation and told of fighting and bloodshed that erupted from price tampering. By the end of Diocletian's reign in 305, the Edict was for all practical purposes ignored. The Roman economy as a whole was not substantively stabilized until Constantine's coinage reforms in the 310s.