Walter J. Foley, 55, a pioneer guided missile systems engineer at the Johns Hopkins University Applied Physics Laboratory, died of cancer Tuesday at Suburban Hospital in Bethesda.

He had helped to develop, test and introduce the first antiaircraft guided missiles in the Navy.

A member of the laboratory's principal engineering staff and a specialist in fire-control systems. Mr. Foley had conducted the early missile flight tests over the western California deserts and at sea.

Named to a task force of defense specialists from the laboratory in the 1950s, he assisted in the introduction of the Terrier missile to factory production at the Pomona, Calif., plant of General Dynamics Corp.

The Terrier and Tartar missiles and the later Talos, developed at the Applied Physics Laboratory, were the firts of their kind to protect a naval fleet. They were installed later on naval ships of several NATO nations.

More recently, Mr. Foley had been in charge of missile integration for the Navy's developing AEGIS fleet defense system. He headed integration of guided missiles with the AEGIS for the first successful at-sea tests off the coast of California in the Pacific Missile Range.

Bron in Rochester, N.Y., Mr. Foley grew up in Attleboro, Mass. He received a bachelor's degree in electrical engineering from Tufts College in 1950. He worked for a short period as an electronic instruments engineer with the Foxboro Co. in Foxboro, Mass, before joining the Applied Physics Laboratory.

During World War II, Mr. Foley had served with the Navy submarine fleet in the Pacific.

He was a member of Tau Beta Pi honorary engineering fraternity, the American Institute of Electrical Engineers and the Knights of Columbus. He was also active in the Boy Scouts.

He is survived by his wife, Louise, a daughter, kathleen M. and a son, Patrick T., all of the home in Silver Spring, and four brothers, James, Lawrence, David and Robert, all of Attleboro.