Walter R. Kosy (1920-1994) was an American engineer and consultant in the field of chemical engineering, specifically plastics.

Born June 12, 1920 in Detroit Kosy graduated from Wayne University in Detroit in 1942 with a degree in Chemical Engineering. From 1942 to 1945, he worked for Lyon, Inc. in Detroit as a metallurgist doing control and development work on cartridge cases. After World War II, Kosy created the plastics department and laboratory for Lyon Inc.

From 1950 to 1955, Kosy was a project engineer on rubber, gasket and plastic problems for Chrysler Corporation in their engineering division. During this time he was also an instructor in rubber and plastics courses at the Chrysler Engineering Institute. He then moved to the General Industries Company in Elyria, Ohio in 1955 as their sales engineer.

Kosy spent the longest part of his career, 1958 to 1980, at Borg-Warner (Marbon) Chemicals, working on sales and engineering of ABS plastics primarily for the automotive industry. In 1980, Kosy formed Plastics Technical Associations and spent the remainder of his professional life a consultant to the plastics industry.

Kosy was a member of the Society of Automotive Engineers, Society of Plastics Engineers, American Society of Body Engineers, and Engineers Society of Detroit.