Greek Registration plates follow a specific format, which comprises of a three-letter combination followed by a four-digit combination, for example ABC 1234, with the letters signifying the area in which the vehicles are registered. Registration plates for motorcycles exceeding 50cc follow a similar format, with the numerical combination running from 1 through to 999. Originally, Greek registration plates were purely numerical, with letters only being introduced as recently as 1972.

With regards to the letter combination, most districts, Athens and Thessaloniki being the only exceptions, take the first two letters as identifiers. The third letter changes alphabetically, after 9,000 plates have been registered. For example, plates from the Achacia district are represented by the letter combination AX. The plates would commence AXA followed by the four numbers, which would run in numerical order. Once the plate AXA 9999 has been issued, the format AXB 1000 would be used. This pattern would continue through to AXX. Incidentally, the Greek alphabet runs A, B, E, Z, H, I, K, M, N, O, P, T, Y and X.

The combinations are slightly different for overseas residents, who are assigned plates with one letter followed by four digits. Taxi drivers followed this same format until 2003 although the letters were red.

Greek registration plates are governed by the rules set out by the Vienna Convention on Road Traffic. Article 35 states that all registration plates display Latin capital letters and Arabic digits.