Spokesman Mike Goss says the shutdowns are likely to take place later this month, affecting about 25,000 workers. But he says no layoffs are expected.
He says the length of the shutdowns is unknown and depends on how fast earthquake-damaged Japanese parts factories get back in operation.
Toyota gets about 15 percent of its parts from Japan for cars and trucks built in North America.
The company has more than a dozen North American factories.
Goss made the comments Monday before an appearance in Louisville by Toyota's head of North American operations.