• A Romanization of the Chinese character 甘 (Gān), an abbreviation for Gansu Province in the People's Republic of China
• A Romanization of the Chinese character 赣 (Gàn), an abbreviation for:
• Gan River
• Jiangxi Province in the People's Republic of China, through which the river flows
• Gan Chinese varieties, which are concentrated in and form the typical speech of Jiangxi
• gan is the ISO 639-3 language code for Gan
• Gan (deity) a deity worshipped in the vicinity of Thistle Mountain, in Guangxi Province, China.
• Gan (Stephen King), the creative overforce in The Dark Tower series by Stephen King
• GAN (cycling team), a French cycling team
• GaN, Gallium(III) nitride, a direct-bandgap semiconductor material of wurtzite crystal structure
• .gan, the file extension for documents created by GanttProject
• gan, an Elvish board game played in The Obsidian Trilogy by Mercedes Lackey and James Mallory

In places:

• Gan, Norway, a village in Fet in Norway
• Gan, Pyrénées-Atlantiques, a commune in the Pyrénées-Atlantiques département in France
• Gan (Huvadhu Atoll), Republic of Maldives
• Gan (Laamu Atoll), Republic of Maldives
• Gan (Seenu Atoll), Republic of Maldives
• Gan International Airport, Maldive by IATA code
• Gananoque, Ontario, Canada, by local nickname

In fictional characters:

• Olag Gan, a fictional character in the British television series Blake's 7
• Gan Isurugi, a fictional character from the Rival Schools video game series

GAN as an acronym may refer to:

• Generic Access Network formerly known as Unlicensed Mobile Access (UMA)
• Giant axonal neuropathy and is also the name of the gene that when mutated causes the disorder.
• Global Area Network