The Grayslake Gelatin Factory is a defunct gelatin factory owned by the Grayslake Gelatin Company, and is located in Grayslake, Illinois. It is locally known for its smoke stack that still rises over the town, which has earned the nickname "Grayslake's Hollywood Sign".
The factory opened in the 1920s as the Wisconsin Milk Company factory. It was conveniently built alongside railroad tracks so deliveries could be made quickly. In the 1950s it became a gelatin factory, and closed production in 1988. Since its opening the factory building was expanded and two additional buildings were built on the property. Employees of the company discovered the modern method of gelatin extraction in 1922. Grayslake Gelatin still has an active office on the property. Gelatin is now sold by Great Lakes Gelatin Company, also located in Grayslake.