In Sweden, vehicle registration plates (Swedish: registreringsskylt) are used for most types of vehicles. They have three letters first, a space and two digits and one digit or letter after (e.g. ABC 123 or ABC 12A). The combination is mostly a random number and has no connection with a geographic location. The last digit is used to show what month the vehicle tax has to be paid, and before 2018 it was also used to show what month the car had to undergo vehicle inspection. Vehicles like police cars, fire trucks, public buses and trolley buses use the same type of plate as normal private cars and cannot be directly distinguished by the plate alone. Military vehicles have special plates. Part of the vehicle data is public and can be retrieved online.

Ordinary plates have black text on a white background. They consist of three letters first, a space, two digits and one more digit or letter. The space was formerly used for a taxation sticker, and on newer plates the space is narrower. Above it a manufacturer code and the vehicle identification number (VIN) are printed and above the last digit the date of plate manufacture is printed. All vehicles must legally carry both a front and a rear plate except for motorcycles, trailers (rear only), tractors and other off-road machinery (front only).

The registration number is tied to the vehicle's VIN and remains unchanged, even after change of ownership, until the vehicle is scrapped or exported. It is possible to decommission a registered vehicle for any length of time. A decommissioned registered vehicle does not require road tax or a valid insurance. The registration plate remains on the vehicle while decommissioned. Registration numbers of scrapped, exported and de-registered vehicles are put in quarantine before they are re-used with new registered vehicles.

All letters in the Swedish alphabet are used, except the letters I, Q, V, Å, Ä and Ö. As of 2019 a letter may be used instead of the last number; this character also excludes the letter O so as not to risk confusion with 0 (zero). 91 additional letter combinations are not used since they may be offensive, political or otherwise unsuitable. Examples include: APA (monkey), ARG (angry), DUM (stupid, bad), FAN (devil, damn), FEG (cowardly), FEL (error, wrong), FUL (ugly), GAY (homosexual), HOT (threat), LAT (lazy), NRP (Nordiska Rikspartiet), OND (evil, cruel), SEX, SUP (snaps), TOA (toilet), UFO, USA, XXL (extra extra large) and many others. MLB (no meaning in Swedish) is reserved for examples, movies, ads and similar, where a real plate connected to a car which might be sold is not desired. English language was not considered when making the list, so for example WTF exists on plates. Until the rules were relaxed somewhat in October 2010, the list included 69 additional exclusions. The Swedish Transport Agency has made this list, which is larger than those in most other countries, to avoid requests to replace issued plate numbers once they are deemed unacceptable, which would cause administrative problems.

Starting in 1994, smaller plates of 30×11 cm were offered for special applications where standard plates would not typically fit, e.g. American domestic market vehicles. These plates are made in a narrower typeface. Up until then large, square plates were used for these applications; however, these were too large height-wise for some American cars, in which case motorcycle plates were issued instead. There is also a self-adhesive plastic 'plate' for use on snowmobiles, ATV's and similar, where the design of the vehicle can make it awkward to fit a real plate. The blue EU stripe was introduced in 2002 as option. As of 1 January 2014 all new manufactured plates have the EU-stripe, and there are no exceptions for older vehicles. Motorcycle owners have often changed plates since it is often hard to find a place for the oval "S"-sticker otherwise needed abroad.

In the middle of the rear plate, a sticker had to be attached to allow driving. This sticker was sent to the owner when the road tax and the liability insurance had been paid and the vehicle had been approved in the inspection. Valid for one year, its colour varied with the year, and the clearly visible month number of expiry could easily be discerned by police. It was introduced in 1973. Since 1 January 2010, the tax sticker was abolished in Sweden, and newer plates have no room for it.

In addition to the ordinary registration plate of three letters and three digits, personal registration plates are allowed. The personal registration plate works as an alias to the ordinary plate and can have (almost) any text or number combination up to seven characters, if it isn't used already. It costs 6200 kr (about 530 €) to get personal number for a vehicle. They are valid for ten years and may be moved to another vehicle. The approval sticker was placed to the left, not in the middle. Text too offensive or illegal is not allowed. For instance, the 64SALE number was not allowed, as the number 6 and the word "sex" are homonyms in the Swedish language.

In 2019 the application for the plate TRUMP was denied because the authority considered it provocative. A sticker declaring the alias relationship between the ordinary plate and the personal plate must be attached in one of the vehicle's windows. The above-mentioned limitation on allowed letters (I, Q, V, Å, Ä, Ö) does not apply to personal plates.