Olgivanna Lloyd Wright, the collaborator and wife of Frank Lloyd Wright and, since his death in 1959, the keeper of his architectural legacy, died of a heart attack yesterday at Scottsdale (Ariz.) Memorial Hospital North. She was 85 years old and lived at Taliesin West, a colony for apprentice architects the Wrights built in the desert near Scottsdale.

A staff architect at the center, Charles Montooth, said yesterday that Mrs. Wright had been recovering from pneumonia brought on by the flu when she was stricken. She had stepped down only last month as president of the Taliesin Foundation, which her husband established in the 1920's in Spring Green, Wis., at the home that later became Taliesin East.

Mrs. Wright, who had become a vice president of the Frank Lloyd Wright Foundation in 1941, became its president after his death. Since 1959, she also headed the Frank Lloyd Wright School of Architecture and Taliesin, which provided training and living quarters for several score aspiring architects in Wisconsin from spring to fall and in Arizona during the winter.

Mrs. Wright was the matriarchal ruler of Taliesin, a self-contained commune where students lived in pavilions hugging the ground near the training center's main buildings. She also composed original music for festivals held at Taliesin and wrote a number of biographical books describing the work, life and philosophy of her husband as well as her own and their life together.

In addition, she was the outspoken defender of all her husband's work, seeking to protect it from wrecking balls and owners bent on changing his facades and interiors.

Granddaughter of a Duke

Mrs. Wright, the former Olga Ivanovna Lazovich, was born in Cetinje, Montenegro, now a constituent republic of Yugoslavia. She was a granddaughter of Marco Milianov, a duke and general in the wars of his mountainous country. His home became a Yugoslav shrine. Her father was Montenegro's chief justice for 30 years. She was educated in the Russian Caucasus and at the Institut Gurdjieff in Fontainebleau, France, before coming to the United States in 1924. She was naturalized in 1933.

She was in the process of divorcing her first husband when she met Mr. Wright at the Russian ballet in Chicago. They were married in 1928, after his divorce from his second wife became final.

In his autobiography, Mr. Wright wrote: ''Just to be with her uplifts my heart and strengthens my spirits when the going gets hard or when the going is good.''

After his death, she paid back in kind with her books, including ''Our Home'' and ''The Shining Brow,'' which reviewers noted for their encomiums and even worshipful tributes to her husband's genius, his philosophy of architecture and the character resources that got him over not a few personal and professional crises.

Translation of Taliesin

''The Shining Brow,'' which appeared in 1960, took its title from the English translation of Taliesin in Mr. Wright's ancestral Welsh.

Upon becoming ill in February, Mrs. Wright relinquished her leadership at the school and foundation, and was succeeded by William Wesley Peters, an architect who has been associated with Taliesin since 1932. He is also a former son-in-law of the Wrights, his first wife, Svetlana Wright, having died in a car crash with their infant son in 1941.

Mr. Peters and life at Taliesin West made headlines across the country in 1970 when he married another Svetlana: Svetlana Alliluyeva, the daughter of Stalin, who had defected to the United States in 1967 and who returned to the Soviet Union last year with their daughter.

She felt, Mrs. Peters said in an interview after leaving Taliesin in 1972, that the Taliesin fellowship was being ''run in a very authoritarian way'' by Mrs. Wright.

Other observers found that she presided over a community shuttling between Wisconsin and Arizona like the abbess of a medieval cloister. Reigning over a spiritual tradition founded by Mr. Wright, his widow was said to have firmly but lovingly ordained the fellowship's architectural operations even though she had no architectural training herself.

She also directed the center's social program and served as counselor to its members.

Mrs. Wright's work as a composer produced chamber music - sonatas, trios, quartets - and orchestral music for the Taliesin Festivals of Music and Dance.

She is survived by her daughter, Iovanna, and two grandchildren.

A memorial service will be held at 4 P.M. today at Taliesin West.

Olgivanna Wright