Kellanova, formerly known as the Kellogg Company, is an American multinational food manufacturing company headquartered in Chicago, Illinois, US. The renaming took effect on October 2, 2023, and the company's North American cereal operations were spun off to form the WK Kellogg Co at the same time. Kellanova produces and markets convenience foods and snack foods, including crackers and toaster pastries, cereal, and markets their products by several well-known brands including Kellogg's, Rice Krispies Treats, Pringles, Eggo, and Cheez-It. Outside North America, Kellanova markets cereals such as Corn Flakes, Rice Krispies, Frosties and Coco Pops.

Kellanova's products are manufactured and marketed in over 180 countries. Kellanova's largest factory is at Trafford Park in Greater Manchester, United Kingdom, which is also the location of its UK headquarters. Other corporate office locations outside of Chicago include Battle Creek, Dublin (European Headquarters), Shanghai, and Querétaro City, Mexico. As Kellogg's, the company held a Royal Warrant from Queen Elizabeth II until her death in 2022.

Kellogg's was split into two companies on October 2, 2023, with WK Kellogg Co owning the North American cereal division, and the existing company being rebranded to "Kellanova", owning snack brands such as Pop-Tarts and Pringles alongside the international cereal division. The purpose of the split was to separate the convenience food, and international cereal products market, from the North American cereal market. Thus facilitating the former Ferrero takeover. "Kellogg's" itself became a brand name of both companies.

Mars Inc., the owner of M&M's and Snickers, agreed to acquire Kellanova for nearly $30 billion in August 2024.

In 1876, John Harvey Kellogg became the superintendent of the Battle Creek Sanitarium (originally the Western Health Reform Institute founded by Ellen White), and his brother, W. K. Kellogg, worked as the bookkeeper. This is where corn flakes were created and led to the eventual formation of the Kellogg Company.

For years, W. K. Kellogg assisted his brother in research to improve the vegetarian diet of the Battle Creek Sanitarium's patients, especially in the search for wheat-based granola. The Kelloggs are best known for the invention of the famous breakfast cereal corn flakes. The development of the flaked cereal in 1894 has been variously described by those involved: Ella Eaton Kellogg, John Harvey Kellogg, his younger brother Will Keith Kellogg, and other family members. There is considerable disagreement over who was involved in the development and the roles that they played. It is generally agreed that, upon being called out one night, John Kellogg left a batch of wheat-berry dough behind. Rather than throwing it out the following day, he sent it through the rollers and was surprised to obtain delicate flakes, which could then be baked.

W. K. Kellogg persuaded his brother to serve the food in a flake form. Soon the flaked wheat was being packaged to meet hundreds of guest mail-order requests after they left the Sanitarium. However, John forbade his brother Will to distribute the cereal beyond his own consumers. As a result, the brothers fell out, and W. K. launched the Battle Creek Toasted Corn Flake Company on February 19, 1906. On July 4, 1907, a fire destroyed the main factory building. W. K. Kellogg had the new plant in full operation six months after the fire.

Convincing his brother to relinquish rights to the product, Will's company produced and marketed the hugely successful Kellogg's Toasted Corn Flakes and was renamed to the Kellogg Toasted Corn Flake Company in 1909 and to the Kellogg Company in 1922. By 1909, Will's company produced 120,000 cases of Corn Flakes daily. John, who resented his brother's success, filed suit against Will's company in 1906 for the right to use the family name. The resulting legal battle, which included a trial that lasted an entire month, ended in December 1920 when the Michigan Supreme Court ruled in Will's favor.