Heat is a sportswear clothing company in Grand Theft Auto: San Andreas, Grand Theft Auto IV and Grand Theft Auto V. Several pedestrians around Liberty City and Los Santos can be seen wearing clothes made by the company, and advertisements can be seen all over San Andreas and Liberty City. As of 2008, Heat has its own website (www.heatbreaktherules.com); unlike other websites for in-game products, it is inaccessible. Heat is also featured in www.peepthatshit.com, and has a theme available to download on www.vipluxuryringtones.com. One of the Heat logos (used primarily in 1992) looks like two Nike logos facing upward; another (used until 2008) is somewhat similar to the Adidas "three stripe" logo. These may be where the inspiration of the brand came from. In GTA San Andreas, Heat's slogan is "Feel the Burn", and in GTA IV, "Break the Rules" (again, possibly a nod to Nike's "Just Do It").
- Gay Tony occasionally wears Heat sportswear instead of his typical business suit, specifically in the missions involving the diamonds where he is present (Frosting on the Cake/Diamonds in the Rough and Ladies Half Price/Diamonds Are a Girl's Best Friend).