The Arizona Republic reported that Thelma Keane died last week of Alzheimer's disease at the age of 82.
Keane served as her husband's business and financial manager as "Family Circus," which started running in 1960, gained in popularity. It is now featured in about 1,500 newspapers.
"I give all the credit to my wife Thel who was the inspiration for all the cartoons," Keane told the Republic. "She was very, very vital to any success that I had."
The couple, who married in 1948, moved to Phoenix in 1959 from Philadelphia, and raised five children.
In addition to her husband, Thelma Keane is survived by her children: Gayle of Napa, Calif.; Neal of Northridge, Calif.; Glen of Santa Clarita, Calif., Jeff of Laguna Hills, Calif. and Christopher of Dragor, Denmark.
Memorial donations can be made to the Sun Health Research Institute in Sun City or the local Alzheimer's Association, the Republic said.