Williams, who had been suffering from bladder cancer for a year, died on Tuesday evening, his family said in a statement.
Known for his hit renditions of "Moon River" and "Born Free," Williams hosted "The Andy Williams Show" on NBC for nearly a decade. The show then became an annual Christmas special.
Williams became entangled in a scandal when his ex-wife Claudine Longet was accused in 1976 of fatally shooting her lover, ski racer Spider Sabich.
The singer announced last year at an appearance at the Moon River Theater in Branson that he was suffering from cancer.
Williams, who grew up in Wall Lake, Iowa, made his professional singing debut at age 8 with his three brothers as part of the Williams Brothers Quartet.
Featured on radio stations nationwide, the brothers eventually drew the attention of Bing Crosby, who joined them to record the 1944 hit "Swinging on a Star."
