What do the letters on a license plate mean?
The letter symbols appearing on license plates always bring curiosity to many people.
In fact, these characters are all regulated in Circular No. 15/2014/TT-BCA regulating vehicle registration issued by the Ministry of Public Security. This Circular regulates the organization of registration, license plate issuance, and road motor vehicles.
State agency license plate
The license plate has a blue background, white letters and numbers, and the license plate series uses one of the following 20 letters: A, B, C, D, E, F, G, H, K, L, M, N, P, S, T, U, V, X, Y, Z issued to vehicles of Party agencies; Office of the President; Office of the National Assembly and agencies of the National Assembly; Office of the National Assembly Delegation, People's Councils at all levels; Central Steering Committees; People's Public Security, People's Court, People's Procuracy; ministries, ministerial-level agencies, agencies under the Government; National Traffic Safety Committee; People's Committees at all levels and specialized agencies under the People's Committees at provincial and district levels; socio-political organizations; public service units, except for public driving training and testing centers; Project management boards with state management functions.

Blue background license plate with white letters and numbers with the symbol "CD" issued to specialized motorbikes of the People's Public Security force used for security purposes.
The license plate has a white background, black letters and numbers, and the license plate series uses one of the following 20 letters: A, B, C, D, E, F, G, H, K, L, M, N, P, S, T, U, V, X, Y, Z issued to vehicles of enterprises, Project Management Boards of enterprises, social organizations, socio-professional organizations, vehicles of non-public career units, vehicles of public driving training and testing centers, and vehicles of individuals.
The license plate has a yellow background, red letters and numbers, has the local registration symbol and two letters abbreviating the special economic-commercial zone issued to vehicles of special economic-commercial zones or international border gate economic zones according to Government regulations.
The license plate has a white background, black numbers, and a red serial number “NG” issued to vehicles of diplomatic missions, consulates, and foreign staff carrying diplomatic identification cards of those agencies. The license plate of Ambassadors and Consulates General has the registration number 01 and an additional red line across the middle of the numbers indicating nationality and registration number.
License plates with a white background, black numbers, and a red serial number “QT” are issued to vehicles of representative offices of international organizations and foreign employees holding diplomatic identification cards of that organization. License plates of heads of representative offices of United Nations organizations have an additional red horizontal line between the numbers indicating the vehicle code of that international organization and the registration order.
The license plate has a white background, black letters and numbers, and the series symbol "CV" is issued to vehicles of administrative and technical staff with official identity cards from diplomatic missions, consular offices, and international organizations.
White background license plate, black letters and numbers, with the symbol "NN" issued to vehicles of foreign organizations, representative offices and individuals.

Some special cases:
License plates with the symbol "KT" are issued to military vehicles for economic purposes.
License plates with the symbol “LD” are issued to vehicles of foreign-invested enterprises, foreign-leased vehicles, and vehicles of foreign companies that win bids.
License plates with the symbol "DA" are issued to vehicles of foreign-invested project management boards.
License plates with the symbol “R” are issued to trailers and semi-trailers.
License plates with the symbol “T” are issued to temporarily registered vehicles.
License plate with symbol “MK” issued to tractors.
License plate with symbol "MĐ" issued to electric motorbikes.
License plates with the symbol "TĐ" are issued to domestically manufactured and assembled motor vehicles, and are permitted by the Prime Minister for pilot implementation.
License plates with the symbol “HC” are issued to cars with limited operating range.