The Heath bar is a candy bar made of toffee, almonds, and milk chocolate, first manufactured by the Heath Brothers Confectionery in 1928. The Heath bar has been manufactured and distributed by Hershey since its acquisition of the Leaf International North American confectionery operations, late in 1996.

In 1913, schoolteacher L.S. Heath bought a confectionery shop in Robinson, Illinois, as a likely business opportunity for his oldest sons, Bayard and Everett. In 1914, the brothers opened a combined candy store, ice cream parlor, and manufacturing operation there.

With the success of the business, the elder Heath became interested in manufacturing ice cream, and opened a small dairy factory in 1915. His sons worked on expanding their confectionery business. At some point, they reportedly acquired a toffee recipe via a traveling salesman, from Vriner's Greek confectionery in Champaign, Illinois. In 1928, they began marketing the toffee confection locally as "Heath English Toffee", proclaiming it "America's Finest".

In 1931, Bayard and Everett were persuaded by their father to sell their confectionery shop and work at his dairy. They brought their candy-making equipment with them and established a retail business there. The Heaths came up with the marketing idea of including their toffee confection on the dairy products order form taken around by the Heath dairy trucks: customers could then order Heath bars to be delivered along with milk and cottage cheese.

Early ads promoted Heath as a virtual health bar – only the best milk chocolate and almonds, creamery butter, and "pure sugar cane". The motto at the bottom of one ad read "Heath for better health!" The motto was surrounded by illustrations of milk, cream, butter, cheese, and ice cream and in a corner – a Heath bar and a bottle of soda. The soda may have been Pepsi, as the Heath Co. bottled the drink for a number of years.

The Heath bar grew in national popularity during the Depression, despite its one-ounce (28 g) size and the 5-cent price, equal to larger bars.

In 1940, family members invested in one of the few available oil leases near Newton, Illinois, that had been overlooked by major oil companies. In July 1940, the lease struck oil, eventually pumping 2,700 barrels per day and earning over $1 million for the family. Two years later in 1942, the U.S. Army placed an order for $175,000 of Heath bars to be included in soldiers' rations. The size of this order led the family to modernize the plant equipment; the candy was manufactured consistently on a major commercial scale thereafter.

Popularity of the Heath bar grew after the war; in 1946, L.S. Heath, his four sons, two daughters and grandchildren incorporated L.S. Heath & Sons, Inc. The manufacturing process remained largely a hands-on, family-run operation. In the 1950s, the Heath Toffee Ice Cream Bar was developed, and was eventually franchised to other dairies. By 1955, the operation had grown to produce about 69,000 candy bar centers at one time. The automatic wrapping machines turned out 1,600 candy bars per minute. The company had 35 candy salesmen who called on approximately 7,200 wholesale distributors in the United States, along with thousands of other outlets, such as theaters, vending machine operators, supermarkets, and chain stores.