AKB48 Group , or AKB48 sister groups, shortened to 48 Group or 48g, refers to the sister groups of the Japanese idol girl group AKB48. Based on the same concept "idols you can meet", it currently consists of five sister groups in locations across Japan and seven sister groups in major Asian cities overseas from Indonesia to Thailand. The Japan-based sister groups not only release their own singles, but also perform on some of the AKB48 singles and events. They also send participants in the AKB48 annual events such as the AKB48 general election. The sister groups outside Japan release local-language versions of the AKB48 singles. In their early development, they are often supported by temporary, concurrent members of AKB48, such as Jurina Matsui and Miyuki Watanabe.

A girl group is a music act featuring several female singers who generally harmonize together. The term "girl group" is also used in a narrower sense in the United States to denote the wave of American female pop music singing groups, many of whom were influenced by doo-wop and which flourished in the late 1950s and early 1960s between the decline of early rock and roll and start of the British Invasion. All-female bands, in which members also play instruments, are usually considered a separate phenomenon. These groups are sometimes called "girl bands" to differentiate, although this terminology is not universally followed.