G1, G01, G.I, G-1, or G One may refer to:

• G1 phase, in the cellular cycle
• G1 regulatory sequence for the insulin gene
• ATC code G01 Gynecological antiinfectives and antiseptics, a subgroup of the Anatomical Therapeutic Chemical Classification System
• Alkali metal, Group 1 of the periodic table
• G1, an informal group of fossil bird eggs from the Gobi desert that were later named Gobioolithus minor

• Contax G1, a Rangefinder camera made by Contax
• DSC-G1, a 2007 Sony Cyber-shot G series camera model
• PowerShot G1, a Canon camera
• Panasonic Lumix DMC-G1, a digital camera made by Panasonic

• Ordnance QF 25 pounder (South African Army designation: G1)
• G-1 (submarine), a class of early-20th century submarines constructed by the Lake Torpedo Boat Company of Bridgeport, Connecticut and purchased by the US Navy
• Char G1, a French tank
• G1, the designation used by the West German and Turkish armies for the FN FAL rifle
• G.I, a German designation for several World War I heavy bombers:
  • AEG G.I
  • Albatros G.I, a German aircraft whose development was the Albatros G.II 1916 aircraft
  • Friedrichshafen G.I
  • Gotha G.I
  • Hansa-Brandenburg G.I, a 1916 bomber aircraft
• Fokker G.I, a 1937 Dutch heavy twin-engined fighter plane
• G-1 military flight jacket, a type of flight jacket
• Kampfgeschwader 55 (historic Geschwaderkennung code G1), with the Luftwaffe in World War II

• G1 Climax, an annual professional wrestling singles tournament held by New Japan Pro Wrestling
• Group One, the highest level races in horseracing

• G1 Aviation G1, French ultralight aircraft
• G1 Beijing–Harbin Expressway, in China
• Alfa Romeo G1, a 1921 Italian car
• Gorkha Airlines (IATA airline designator)
• One of the G-series Toronto subway cars

• G1 (website), a Brazilian news portal owned by Grupo Globo
• G1 Group, a Scottish hospitality and leisure operator
• G1 licence, the first tier in the graduated licensing programme for Ontario's new drivers
• G.One (character), an android super hero
• Gangwon No.1 Broadcasting, a Seoul Broadcasting System television channel in Gangwon Province
• Godzilla Minus One, a 2023 kaiju film often abbreviated to G–1
• T-Mobile G1, the first publicly available Android smartphone
• Transformers: Generation 1, a toy line which ran from 1984 to 1992
  • The Transformers (TV series), an animated television series meant to promote the toy line (popularly referred to as Generation 1)

• 1G (disambiguation)
• G (disambiguation)

This disambiguation page lists articles associated with the same title formed as a letter–number combination.
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