The Sasanian Empire ( or ), also known as Sassanian, Sasanid, Sassanid or Neo-Persian Empire), known to its inhabitants as Eranshahr in Middle Persian language, was the last Iranian empire before the rise of Islam, ruled by and named after the Sasanian dynasty from 224 to 651. The Sasanian Empire, which succeeded the Parthian Empire, was recognized as one of the leading world powers alongside its neighboring arch rival the Roman-Byzantine Empire, for a period of more than 400 years.

Das Sassanidenreich war das zweite persische Großreich des Altertums. In der jüngeren Forschung hat sich die etymologisch korrektere Schreibweise Sasaniden gegenüber der lange Zeit gebräuchlichen Schreibweise Sassaniden weitgehend durchgesetzt.