The Isuzu Elf (Japanese: いすゞ・エルフ, Hepburn: Isuzu Erufu) is a medium duty truck produced by Isuzu since 1959. Outside Japan it is known as N series and Q Series. The range was originally mainly available in Japan and other Asian countries. Australia was another important market for the Elf and N series – to the extent that it was manufactured there from the 1970s using many local components. Since the early 1980s, it has also been sold and built in the United States (under the Chevrolet and GMC brands as a W-Series), and also as the Isuzu N-Series. Only North America receives the wide-cab version.

For the common Andinian market (including Chile and Peru), the truck has been assembled in the GM-Colmotores assembling plant in Bogotá, Colombia since 1991, with annual quantities already of 20,000 up to 60,000 units. Local assembly has been increasing because of increasing demand in the Colombian and neighboring markets. It carries "Tecnología Isuzu" (with Isuzu Technology) lettering.

In Indonesia, Philippines, and several other countries, the Elf is not only used as a truck, but also converted into microbuses by local body makers. The lighter four-wheeled models are commonly used as an intercity Angkot or Jeepney (share taxis), as a school bus, or as an employee bus. Indonesian conversions typically use car-style hinged doors and usually resemble a high-roof van, while most conversions in Kenya, and newer ones in the Philippines often resemble a minibus, with a folding door on the side for passengers, and standing room.

The cab-over 2-tonne (4,400 lb) Elf (TL221) was originally introduced in August 1959. It was originally only available with the 1.5 L (1,491 cc) GL150 petrol engine rated at 60 PS (44 kW). It had single headlights and rear-hinged doors. A longer wheelbase version, on 2,460 mm (97 in) versus the 2,180 mm (86 in) of the regular version, was also available. This carries the TL251 chassis code.

In March 1960, a 2.0-liter diesel engine rated at 52 PS (38 kW) was introduced (TL121/151), a first for the class in Japan - this was soon followed by diesel models from Isuzu's competitors. In 1962 the engines were updated, and were now rated at 72 and 55 PS (53 and 40 kW) respectively. The chassis codes were changed to TL321/351 for the diesel version, reflecting the installation of the all new DL201 engine. A little later on, the chassis codes were reorganized and were now TLG10/11 for the petrol models and TLD10/11 for the diesels. In 1964, the long wheelbase model became the standard version. In 1964, the diesel version was also upgraded to the larger 2.2-litre C220 engine rated at 62 PS (46 kW). In 1965, the Elf received a facelift, now having twin headlights.

Isuzu ended up offering a very wide variety of bodyworks for the first generation Elf. These include the original integrated bed, as well as a separate truckbed with dropsides. There was a double-cab version available, as well as special bodywork for dedicated purposes such as a soda truck, a dumper, and a tanker. There was also a "Route Van" model with a glazed rear compartment and seating either three or six passengers, as well as the "Elf Bus" which was available in two models from 1960. The Elf Light Bus has integrated bodywork with the long wheelbase and seats 21 passengers (chassis codes BL171/271 for the diesel/petrol) while the Elf Micro Bus fits into the very narrow slot between the Route Van and the Light Bus. The Micro Bus originally had the Route Van's bodywork but was more passenger-oriented (seating 12 or 15). It carried the TL121/151/21/251B chassis codes, and from 1961 it received its own rear bodywork with bigger glazing. The Elf Bus later became its own line, called the Isuzu Journey.

In August 1967, the all-new "Isuzu Light Elf" was added to the existing lineup; this lighter duty version was rated for a 1.25-tonne payload (2,800 lb). It had single round headlights and a KA-series chassis code; it came with the same 1,471 cc (1.5 L) G150 engine as fitted to period Isuzu Belletts, rated at 68 PS (50 kW). This was the first of the second generation Elfs to be introduced, heavier duty models soon followed and replaced the first generation variants.

In April 1968, the second generation Elf appeared (TL21/TLD21 series). A walk-through van ("Elf Hi-Roof") was also introduced, another first for Japan. In September 1969, the "Light Elf" was upgraded to 1.5-tonne (3,300 lb) and now offered a more powerful 1.6-liter engine (G161AB) rated at 75 PS (55 kW). In October 1970, this part of the range became the Elf 150 while the regular Elf (2-2.5 tonnes) became the Elf 250; the 250 was updated to a 2.4-litre diesel engine. This was combined with the introduction of the heavier duty, 3.5-tonne (7,700 lb) Elf 350. This re-shake of the lineup was then followed by the very modern Elf Mi-Pack in April 1972. The Mi-Pack was a front-wheel drive model with a flat and low loading floor, only 450 mm (18 in) off the ground. Because of its high price combined with customer reluctance to a front-wheel drive truck it was retired after only a few years on the market. Instead a low-floor model of the Elf 150 was added to the lineup in 1974, featuring small twinned rear tires.