TGI

TGI may refer to:
 * Technical Group of Independents (1999–2001)
 * The Genome Institute
 * The Ghost Inside (band), an American band formed in 2004
 * TGI Friday's, a restaurant chain
 * Thermal grill illusion, a sensory illusion originally demonstrated in 1896 by the Swedish physician Torsten Thunberg
 * Thyroid growth immunoglobulin, found in Graves' disease
 * Tribunal de grande instance de Paris
 * Triumph Group's NYSE ticker symbol
 * Target Group Index, a subsidiary of market research company Kantar Group