The zoo keeper was alert and awake when she was rushed to a hospital, where she was listed in stable condition, City of Topeka spokeswoman Molly Hadfield said by phone.
The Topeka Zoo & Conservation Center was open to visitors when the male tiger named Sanjiv injured the worker, whose normal assignment was tending to the tigers, Hadfield said.
The zoo was closed for 45 minutes and its six tigers, including the 7-year-old Sanjiv, were placed in a holding pen after the attack.
The incident was under investigation but zoo officials did not plan any repercussions for Sanjiv.
"Nothing is going to happen to our tiger," Hadfield said.
Sumatran tigers are critically endangered, with fewer than 400 living in the wild, according to the World Wildlife Fund.Sanjiv came to the Topeka Zoo in 2017 from a zoo in Akron, Ohio. Four of Sanjiv's cubs are on display at the Topeka Zoo.