The Trøndelag Commuter Rail (Norwegian: NSB Lokaltog Trøndelag, previously Trønderbanen) is a commuter train service operating in Nord-Trøndelag and Sør-Trøndelag, Norway. It is operated by Norwegian State Railways (NSB) with Class 92 diesel multiple units. The service provides a commuter service connecting Trondheim to its suburbs, between towns in Innherred and as an airport rail link for Trondheim Airport, Værnes. Although passenger services have operated along the lines since 1864, the commuter train was created with an increase of service with existing rolling stock in 1993. In 2006, the system had at least 1,180,000 passengers.

The main service operates from Lerkendal in Trondheim via Trondheim Central Station and Trondheim Airport Station to Steinkjer on the Nordland Line. The service runs every hour, with additional rush-hour services, and reduced service in the evenings and on the weekend. A secondary services runs from Trondheim along the Dovre Line to Støren and along the Røros Line to Røros. The Mittnabotåget service operates twice a day from Trondheim along the Meråker Line and the Central Line in Sweden to Östersund Central Station.

Trøndelag is the name of a geographical region in the central part of Norway, consisting of the two counties Nord-Trøndelag and Sør-Trøndelag. (The districts of Nordmøre and Romsdal, and the municipality of Bindal, originally also were parts of Trøndelag - and the inhabitants there still speak dialects similar to Trøndersk.) The region is, together with Møre og Romsdal, part of a larger administrative division called Central Norway.

A person from Trøndelag is called a Trønder. The largest city, unofficial capital of Trøndelag and also the first capital of Norway, is Trondheim (Sør-Trøndelag). The dialect spoken in the area is characterized by dropping out most vowel endings; see apocope.

The Norse form of the name was Þrœndalǫg. The first element is the genitive plural of þrœndr m 'person from Trøndelag', the last element is lǫg (plural of lag n) 'law; district/people with a common law' (compare Danelaw, Gulaþingslǫg and Njarðarlǫg). A parallel name for the same district was Þróndheimr 'the home/homeland (heim) of the þrœndr '. The last name is probably older since the first element has a stem form without umlaut.

Commuter rail, also called suburban rail, is a passenger rail transport service that primarily operates between a city center, and the middle to outer suburbs beyond 15 km (10 miles) and commuter towns or other locations that draw large numbers of commuters—people who travel on a daily basis. Trains operate following a schedule, at speeds varying from 50 to 200 km/h (30 to 125 mph). Distance charges or zone pricing may be used.

Non-English names include Treno suburbano in Italian, Cercanías in Spanish, Nahverkehrszug in German (and in most larger cities S-Bahns though these trains also often include city centre metro-like sections where lines have merged and services become more frequent, and stations are closer together to better distribute passengers into the city core),Train de banlieue in French, Příměstský vlak in Czech and Elektrichka in Russian. The development of commuter rail services has become popular today, with the increased public awareness of congestion, dependence on fossil fuels, and other environmental issues, as well as the rising costs of owning, operating and parking automobiles.