The G Line (formerly the Orange Line) is a bus rapid transit line in Los Angeles, California, operated by the Los Angeles County Metropolitan Transportation Authority (Metro). It operates between Chatsworth and North Hollywood stations in the San Fernando Valley. The 17.7-mile (28.5 km) G Line uses a dedicated, exclusive right-of-way for the entirety of its route with 17 stations located at approximately one-mile (1.6 km) intervals; fares are paid via TAP cards at vending machines on station platforms before boarding to improve performance. It is one of the two lines in the Los Angeles Metro Busway system and the only one not to serve Downtown Los Angeles.

The line, which opened on October 29, 2005, follows part of the Southern Pacific Transportation Company's former Burbank Branch Line, which provided passenger rail service from 1904 to 1920; it was subsequently used by Pacific Electric streetcars from 1911 to 1952. At North Hollywood station, the G Line connects with the B Line subway, which offers service to again Downtown Los Angeles via Hollywood. The G Line Bikeway runs alongside part of the route.

In 2020, the line was renamed from Orange Line to the G Line while retaining the color orange in its square icon as part of a complete renaming of lines by Metro.

Because of its many differences from standard bus service, Metro has branded the G Line as part of the region's network of light and heavy rail lines, and it appears on the same system map as the rail lines. The buses are painted in the silver-and-gray color scheme of Metro Rail vehicles. The G Line is rarely referred to by its line number (901), but it sometimes appears on documents and destination signage.

The G Line's icon color, and former Orange Line name, were inspired by the many citrus trees that once blanketed the San Fernando Valley. In the planning stages, the G Line was known as the San Fernando Valley East-West Transitway and later the Metro Rapidway.

G Line buses operate 24 hours a day. At peak hours (between 6 am and 7 pm eastbound, 5 am and 6 pm westbound), every other bus is a short turn, only operating between North Hollywood and Canoga station.

The following is the complete list of stations, from west to east. Each station is located within the city limits of Los Angeles.

Stations	Date Opened	Neighborhood	Major connections and notes
Chatsworth	June 30, 2012	Chatsworth	Pacific Surfliner  Ventura County Park and ride: 609 spaces
Nordhoff
Roscoe		Canoga Park
Sherman Way			Park and ride: 207 spaces
Canoga	December 27, 2006		Park and ride: 246 spaces
De Soto	October 29, 2005	Winnetka
Pierce College			Park and ride: 392 spaces
Tampa		Tarzana
Reseda			Park and ride: 442 spaces
Balboa		Lake Balboa	Park and ride: 273 spaces
Woodley		Van Nuys
Sepulveda			Park and ride: 260 spaces Future connection to Sepulveda Transit Corridor
Van Nuys			Park and ride: 307 spaces Future connection to East San Fernando Valley Light Rail Transit Project (2030)
Woodman		Valley Glen
Valley College
Laurel Canyon		Valley Village
North Hollywood		North Hollywood	Park and ride: 1,085 spaces

The majority of the G Line is built on part of the former Southern Pacific Railroad Burbank branch, part of which saw Pacific Electric Red Car service (see San Fernando Line and Owensmouth Line); passenger service on this segment ended in 1952, but the right-of-way remained undeveloped and was acquired by Metro in 1991. As the Metro Rail system was being designed in the 1990s, initial plans were to build an extension of the Metro Red Line there, since the purchased right-of-way's eastern terminus was at the site of the planned North Hollywood station. However, political developments stymied these plans: community objections to surface transit along the route resulted in a 1991 law mandating that any line along the route be built as a deep-bore tunnel, but a 1998 ballot measure driven by perceptions of mismanagement banned the use of county sales tax to fund subway tunneling. Prevented from using the route for rail, Metro proceeded to create its first bus rapid transit line along the corridor, and despite further lawsuits from area residents, the line opened on October 29, 2005, at a final cost of US$324 million or US$23 million per mile (US$505 million and US$35.9 million in 2023 adjusted for inflation).

Then-County Supervisor Zev Yaroslavsky said they initially mirrored the busway concept based on a similar transit system he, then-Mayor Richard Riordan, and other elected officials toured in Curitiba, Brazil.

On June 23, 2009 construction began on a four-mile (6.4 km) extension from Canoga northward along the Southern Pacific trackbed to the Metrolink station in Chatsworth. Metro's board approved the plan on September 28, 2006, and it was completed in 2012 at a cost of US$215 million (US$285 million in 2023 adjusted for inflation). This created two branches at the western end of the line beyond Canoga station; the older branch proceeded outside the busway on city streets to Warner Center. In 2018, this branch was eliminated and replaced with a frequent service local shuttle, leaving the entirety of the Orange Line on the dedicated right-of-way.

In the first year that the busway was open, there were ten injury collisions between vehicles and buses, which were heavily covered in the media. Metro noted that the buses had about the same accident rate as other bus lines in the city on a per-mile basis, and has stated that the line's accident rate is "less than half" of Metro's entire fleet of buses. They also pointed out that the A Line also had a significant number of collisions in its early years. Under pressure, Metro ordered buses to slow from 25–30 mph (40–48 km/h) to 10 mph (16 km/h) at intersections. Starting in December 2005, red light cameras were installed at most intersections.

As part of the enhancement package to the LA Metro system approved by voters in 2016 with Measure M, in October 2017, Metro recommended a series of improvements to the Orange Line. These include quad-crossing gates at 37 intersections and constructing a mile-long elevated section between Sepulveda and Van Nuys Boulevard. These improvements would eliminate much of the time Orange Line buses spend waiting at red lights, would allow buses to cross intersections at higher speeds, and cut end-to-end travel time along the entire route by 29%. Projected construction costs are US$283 million.

Metro advertised a design–build project in February 2022 to convert 41 existing signalized intersections on the G Line from transit signal priority to preemption using railroad-grade-crossing-style gates and flashing light signals (similar to the prototype proof of concept at the Hayvenhurst Avenue pedestrian crossing). The project also calls for building an aerial busway and two aerial stations to grade separate three other intersections (Sepulveda, Vesper, and Van Nuys). The plans require all work to be compatible with the future conversion of the busway to the light rail. Pre-construction has started with the LADWP burying the aerial power lines at the busway intersection with Sepulveda in Van Nuys. As of October 2022, Metro expects construction to begin in 2023, and the project will be completed in 2026.

There is concern that the G Line will soon reach its engineered capacity and has exceeded its designed capacity during peak periods. Adding more buses requires platooning (running convoys of two or more buses together), similar to what rail achieves in having multiple cars per train. And while the proposed change in the previous project from priority to preemption at signalized intersections will decrease delays to G Line buses, it will come at the cost of increasing cross-street travel times and reducing their capacity since priority balances the timing needs of busway traffic with cross-traffic versus the more disruptive railroad-style preemption. Another alternative involves using longer vehicles to increase each bus's capacity. In 2015, California passed a bill allowing buses up to 82 feet long to operate on the G Line busway (longer than the existing 65-foot-long articulated buses.)

In April 2015, a report prepared for Metro estimated that conversion of the G Line to light rail would take two to three years and cost between US$1.2 and 1.7 billion. This price would include both upgraded infrastructure and the purchase of rail vehicles. The report noted that if not upgraded in some way shortly, the G Line would soon reach capacity at rush hours. Full conversion to light rail is planned to take place by 2050. Different braking distances of LRT vs. BRT might be an essential concern of safety tests.

On October 27, 2005, two days before the line's official opening, a motorist driving with a suspended license ran a red light and collided with an eastbound bus at Vesper Avenue. There were no injuries.

In November 2005, there were two collision-caused injuries. In the first, a fare inspector on the bus was taken to a hospital for minor injuries after a 65-year-old female driver made an illegal right turn against a red light and struck an Orange Line bus near the crossing at Corbin Avenue in Reseda. In the second, one person was seriously injured and 14 others hospitalized after an elderly motorist ran a red light while using a mobile phone. After the second collision, Metro instructed all buses to slow down at intersections and installed white strobe lights on the sides of the buses to improve visibility. They said they would review any and all ideas to improve safety on the line.

In October 2006, a delivery truck hit the side of a bus. One person was seriously injured, and 16 received minor injuries.

The G Line has a dedicated fleet of 60-foot (18 m) articulated buses that each have 57 seats—about 50% more than 40-foot (12 m) non-articulated buses—and have three doors (versus two on non-articulated buses). The G Line uses a proof-of-payment system whereby fares are paid before boarding, so the buses do not have any onboard fare collection equipment. The G Line fleet is stored and maintained at Metro's Division 8 depot in Chatsworth, which has direct access to the busway.

Prior to 2021, the former G Line fleet used NABI 60-BRT buses which ran on compressed natural gas (CNG). In 2021, all NABI 60-BRT buses were replaced with 40 New Flyer Xcelsior XE60 battery electric articulated buses. Additional features of the battery electric buses include dual air conditioning units, two additional hub-mounted motors on the middle axle, an active suspension system, USB charging ports at each seat, and public Wi-Fi. They also lack the large cooling fans of the CNG buses, which makes them quieter.

Each battery-electric bus has a battery capacity of 320 kW-hr, which provides a range of about 150 miles (240 km). There are ten 150 kW slow chargers at the bus depot, as well as 450 and 600 kW on-route rapid chargers at the Canoga, Chatsworth, and North Hollywood stations. The on-route chargers, which are manufactured by Siemens to the SAE J3105-1 standard, add about 40 miles (64 km) of range from a seven to ten-minute charge. Both types of chargers have overhead pantographs that connect to roof-mounted contacts on the buses. The depot chargers use a one-to-many scheme, whereby 150 kW from a single charger is distributed to multiple overhead pantographs. The electrification project cost US$80 million, including the buses (US$1.15 million each), charging equipment, and infrastructure improvements.

As of the end of June 2024, due to heat stress and reliability issues with on route charging equipment, Metro has begun intermittently using 40-foot (12 m) CNG powered buses to supplement the dedicated battery-electric fleet. This goes back against the G Line's electrification achievement, a long-standing Metro-touted victory in its troubled history of attempting to electrify its bus fleet. Though many of Metro's previous failures have been attributed to its dealings with BYD, the problematic charging equipment on the G Line is manufactured by Siemens, and the buses on the G Line are manufactured by New Flyer.

The G Line Bikeway is an active transportation bicycle path that shares the right-of-way with the G Line busway.

• List of Los Angeles Metro Busway stations
• List of Los Angeles bike paths

• G Line page at LA Metro
• LA Metro: Orange Line Extension – 4 miles (6.4 km) extension under construction from Canoga Station north to Chatsworth Metrolink Station (2012).
• Orange Line history
• Light Rail Now: "A Bus by Any Other Name Is Still ... a Train ? " – by The Light Rail Now project.
• Biking the Orange Line