John Holland Treanor, 75, an outspoken educator who thought that "most teachers would not know English composition if it walked down the street and hit them in the face," died of pneumonia Tuesday at the Manor Care nursing home in Hyattsville.

Mr. Treanor was a teacher and principal in Boston public schools for almost 30 years. The author of a widely used set of textbooks called "The Treanor English Series," he also was a teacher, as well as a critic, of English teachers. He was a consultant to the D.C. public schools in 1967. "They're mostly the elderly teachers. Twenty-five per cent should be thrown out the window. The rest usually have a poor cultural background that is reflected in their speech and vocabulary. And in their teaching."

Mr. Treanor made his remark about most eachers not knowing composition if it walked down the street at a meeting of the Council for Basic Education here in 1960.

In his view, the purpose of studying English was to learn to speak and write clearly. He thought this was a matter of emphasizing fundamentals and even teaching them by rote if necessary.

He thought elementary shcoolchildren should be taught the elements of grammar. As they mastered them, they should use these elements in sentences.Junior high school students should be taught about the paragraph and not just the fact "that it's indented." High school students should be taught composition.

Mr. Treanor's textbooks, which were written for children in the third through the eight grades, were published by the McMillan Co. and were used in many D.C. schools as well as in public and Catholic schools elsewhere in the country.

Mr. Treanor was born in Pittsfield, Mass, and grew up there in Boston. He graduated from Holy Cross College and later earned a master's degree in English from Boston College. He began his teaching career in the Boston public schools in 1933. At the time he resigned in 1950 to devote full-time to lecturing and consulting work, he had been headmaster of the Francis Parkman School District in Boston for 12 years.

He maintained his residence in Jamaica Plain, Mass, during his years as a consultant here and elsewhere. He moved to this area in 1972. In all, he visited about 700 school systems in the United States. He published more than 200 articles in professional journals.

Survivors include his wife, Helen B., of Washington; two sons, John H. Jr., of Annapolis, a former member of the D.C. Board of Education, and Richard B., of Washington; a brother, Gerard F., of Washington; two sisters, Gertrude Treanor, of Tequesta, Fla., and Mrs. Frank Conroy, of West Roxbury, Mass., and one grandchild.