Illinois Tool Works Inc. or ITW is a Fortune 500 company that produces engineered fasteners and components, equipment and consumable systems, and specialty products. It was founded in 1912 by Byron L. Smith.

Today, it employs nearly 48,000 people in hundreds of businesses across 57 countries, and is based in Glenview, Illinois, a suburb of Chicago, Illinois.

In 2011, ITW had more than 20,000 unexpired patents and pending patent applications worldwide, including 2,900 U.S. patents and 1,116 pending U.S. applications. The company typically ranks in the top 100 of patent issuers in the U.S. It is ranked 414 on the Forbes Global 2,000.

Illinois Tool Works Ring carriers produce about 47% less emissions released into the atmosphere than paperboard cartons and about 36% less than shrink-film 6-pack packages. From taking a look at their activities, environmental coordinators were able to have certain products reformulated to less environmentally damaging products. Also, certain processes were amended to have a reduced environmental impact.The company took another look at the possibilities of reducing and recycling waste, maximizing the efficient use of natural resources, and delivering environmental awareness training to the whole of the work force. This last activity led to the creation of an Environmental Team comprising seven volunteers from the workforce to further environmental improvements and in March 2004 the Company received Green Dragon Level 5 Standard. The Political Economy Research Institute ranks ITW 100th among corporations emitting airborne pollutants in the United States. The ranking is based on the quantity (0.9 million pounds in 2005) and toxicity of the emissions.

The United States Department of Commerce imposed a $142,000 civil penalty on Illinois Tool Works in 2000, to settle allegations that the company illegally exported chemicals to Brazil on seven occasions between March 1994 and October 1997 without the required licenses and making false or misleading statements on Shipper's Export Declarations. Illinois Tool Works agreed to pay the penalty. $37,000 was suspended as part of the settlement. The chemicals exported can be used for commercial purposes and in the making of chemical weapons as well.

ITW comprises a number of companies and divisions. Notable brands include Miller Electric, DUO-FAST fasteners, Foster Refrigerator, and the Wolf Range Company.

The following is a list of ITW companies: