ASTM International, formerly known as American Society for Testing and Materials, is a standards organization that develops and publishes voluntary consensus technical international standards for a wide range of materials, products, systems and services. Some 12,575 apply globally. The headquarters is in West Conshohocken, Pennsylvania, about 5 mi (8.0 km) northwest of Philadelphia. It was founded in 1902 as the American Section of the International Association for Testing Materials.

In addition to its traditional standards work, ASTM operates several global initiatives advancing additive manufacturing, advanced manufacturing, and emerging technologies, including the Additive Manufacturing Center of Excellence (AM CoE), the acquisition of Wohlers Associates for market intelligence and advisory services, and the NIST-funded Standardization Center of Excellence (SCOE).

In 1898, a group of scientists and engineers, led by chemist, industry leader, and proponent of standardization Charles Dudley, formed the American Society for Testing Material (ASTM) to address the frequent rail breaks affecting the fast-growing railroad industry. The group developed a standard for the steel used to fabricate rails.

In 1961 the name "American Society for Testing and Materials" was adopted.

In 2001, ASTM officially changed its name to "ASTM International" and added the tagline "Standards Worldwide".^{[citation needed]}

In 2014, the tagline changed to "Helping our World Work better." ASTM International had offices in Belgium, Canada, China, Peru, Washington, D.C., and West Conshohocken, PA.

In April 2016, the Safety Equipment Institute (SEI) became a subsidiary of ASTM International. SEI is an accredited third-party certification organization that certifies various types of PPE^{[clarification needed]} to industry consensus standards.

On June 9, 2022, it was announced that the European Committee for Standardization (CEN) and ASTM International agreed to extend and expand a Technical Cooperation Agreement from 2019.