Johnny Weissmuller, the Olympic swimming champion who went on to fame as Tarzan of the Jungle in the movies, died at his home here Friday night, according to a funeral home. He was 79 years old.

Luis Flores of the Gomez funeral home said Mr. Weissmuller's wife, Maria, had not completed funeral arrangements but that burial would probably be Sunday in Acapulco.

Mr. Weissmuller had been an invalid since moving here in late 1979. He suffered a series of strokes in 1977 and had a history of heart disease. His home was a few miles from the lake where his last Tarzan film was shot.

Man of Two Careers

Few of the millions of Tarzan lovers who thrilled to Mr. Weissmuller swooping from tree to tree or locking in lethal combat with lions or crocodiles ever knew him as the swimming phenomenon who won five Olympic gold medals and set 67 world records in the 1920's.

Sports enthusiasts then thought that the records, all set before Mr. Weissmuller was 25 years old, would endure for decades. But most of them were eclipsed by the time the casual, carefree Mr. Weissmuller went to Hollywood and filmmakers in 1932 began molding his image as a brawny, monosyllabic friend of apes and elephants.

He made close to 20 Tarzan films, the last one in 1949. In all of them he was something of a howling jungle Superman in loincloth, the benevolent protector of his African domain and the treetop home of his wife, Jane, and his son, Boy, and the vanquisher of villains, marauders and ivory hunters.

The image has been perpetuated through the years on television reruns of the films and they led children and adults to approach Mr. Weissmuller for a Tarzan autograph and for yet another rendition of his elephant call or his chest-thumping victory bellow.

Enjoyed the Life

Playing Tarzan, he said over the years, ''was right up my alley.''

''It was like stealing,'' he said. ''There was swimming in it, and I didn't have much to say. How can a guy climb trees, say 'Me Tarzan, you Jane,' and make a million?''

''The public forgives my acting because they know I was an athlete,'' he said on another occasion. ''They know I wasn't make-believe.''

As a swimmer, Mr. Weissmuller was without peer in his time. A remarkably buoyant 190-pounder, he seemed to glide across the water, his broad shoulders and heavily muscled back protruding above the surface.

His six-beat crawl stroke produced the speed. The style calls for six beats of the legs for every two arm strokes, with absolute synchronization of feet and arms. His power came from a full arm pull, from the moment each hand struck the water until it emerged.

From August 1921, when as a 17- year-old he broke his first world record, until he turned professional in January 1929, he set and reset world and national freestyle records for distances from 50 yards to a half mile.

Grew Up in Chicago

Peter John Weissmuller was born in the southwestern Pennsylvania town of Windber on June 2, 1904, shortly before his Vienna-born parents moved to Chicago. He dropped out of school in the eighth grade, shortly before the death of his father, who had become a brewmaster. The boy learned to swim at about age 9 in the city's public pools and in Lake Michigan.

As a lanky 15-year-old who outdistanced rivals in impromptu swimming races, the youth attracted the attention of Bill Bachrach, the swimming coach of the Illinois Athletic Club.

A strict, formal training regimen was quickly applied. Before the 1924 Olympics in Paris, Mr. Weissmuller supplanted Duke Kahanamoku of Hawaii and Perry McGillivray as champion in the 100-yard freestyle and he beat Norman Ross at longer distances.

At the Amateur Athletic Union national championships in 1923, he won the freestyle events at 50, 100, 220 and 500 yards and then captured the 150- yard backstroke, cutting six seconds off the world mark.

He captured three of his gold medals at age 20 in the 1924 Olympics, winning the 100-meter and 400-meter freestyles in Olympic record times of 59 seconds and 5:04.2, and anchoring the 800-meter freestyle relay team that produced a world record of 9:53.2.

In the 1928 Olympics in Amsterdam, he won his fourth and fifth gold medals, in the 100-meter race and anchoring the 800-meter relay team.

After turning professional, Mr. Weissmuller endorsed bathing suits for a while. Then Hollywood hired him as the screen industry's Tarzan, based on the character created in print by Edgar Rice Burroughs.

Mixed Critical Reception

Film critics were generally amused with his antics and impressed with the photography in the first three Weissmuller films, ''Tarzan, the Ape Man,'' in 1932; ''Tarzan and His Mate,'' in 1934, and ''Tarzan Escapes,'' in 1936. Maureen O'Sullivan was cast as Jane Parker, the British woman who spurned her fiance in a hunt and went to live with Tarzan after her father was killed.

Later Tarzan films were box-office bonanzas, but the critics wearied of the repetitive plots and Tarzan's stunted diction, and in 1949, with Mr. Weissmuller 45 years old, his girth expanding, the role was taken over by Lex Barker.

Mr. Weissmuller began making new films, and later a television series, as ''Jungle Jim.'' That work lasted until the late 1950's.

From 1965 until November 1973, Mr. Weissmuller lived in Fort Lauderdale, Fla., with Maria, his last wife, a native of Bavaria. Earlier wives, all of whom sued for divorce, were Robbe Arnst, a musical comedy actress; Lupe Velez, the Mexican actress; Beryl Scott, the San Francisco socialite who bore his three children, John Scott, Wendy Ann and Heidi Elizabeth (who died in a car crash at the age of 19 in 1962), and Allene Gates, a golfer from Los Angeles.