A Bag for life is a type of bag offered in most UK and Irish supermarkets. In the UK, these are sold for a nominal sum, usually 10 pence, and are replaced for free. In Ireland, they were introduced when the Plastic Bag Environmental Levy was brought in to reduce the massive amount of disposable bags being used anually. Bags costing 70 euro cents or more are exempt from the levy.

The main purpose of this is to ensure that the bags are recycled (which usually earns the retailer a small amount of money per bag), and unlike with free carrier bags there is a (small) financial incentive to bring the bags back for recycling, lessening the environmental impact.

In contrast to more spartan carrier bags, bags for life tend to be colourful and show some aspect of the supermarket's advertising. Some supermarkets maintain the same design for years at a time, whereas some, like Waitrose, rotate the designs to tie in with either the season or the most recent advertising campaign.