Robert John Holthaus (December 28, 1928 – August 2, 1985), better known as Bob Holt, was an American actor, best known for his voice work.

He later appeared in such works as Bedknobs and Broomsticks, several animated television specials with Dr. Seuss, for example, The Lorax (1972), Dr. Seuss on the Loose (1973), The Hoober-Bloob Highway (1975) and The Grinch Grinches the Cat in the Hat (1982) and the animated film version of Charlotte's Web as Homer Zuckerman.

The same year, Holt provided the voice of Avatar in Ralph Bakshi's film Wizards.

In 1982, Bob Holt played the title role in Marvel Productions' animated The Incredible Hulk (1982 TV series), also in the process creating a library of stock roars that would be used for many years afterwards.

Holt died of a heart attack on August 2, 1985, in Van Nuys, California.