A heat sealed bag, also known as a heat-sealable bag, is a type of packaging that is sealed using heat to create a secure and tamper-resistant closure. This sealing method involves applying heat to the bag's opening, which activates a heat sensitive adhesive or causes the bag's material to melt and fuse together, forming a strong seal.

Heat sealed bags are commonly made from materials such as plastic films, including polyethylene (PE) or polypropylene (PP). These materials have the property of becoming pliable and adhesive when heated, allowing them to bond together and create an airtight and watertight seal.