The 42-year-old lieutenant governor told the Associated Press Thursday that she's under a doctor's order not to attend the fair.
Hundreds of people congregate there in the summer heat to hear speeches, shake hands and socialize.
The fair's political speeches are scheduled for July 28 and 29. Tuck was scheduled to have a prime speaking time on the first morning.
Also expected to skip the fair this year is House Speaker Billy McCoy. The 61-year-old lawmaker remains in Mississippi Methodist Rehabilitation Center in Jackson as he recovers from diverticulitis, an inflammation of the digestive tract.
Surgeons at the University of Mississippi Medical Center on June 5 removed about a foot of McCoy's colon.