"When your name is TENNESSEE, it's a bit tricky to learn how to spell it," Witherspoon captioned the cute pic, which she tagged "#PreSchoolProblems"
Witherspoon and her husband, Jim Toth, welcomed Tennessee in September 2012. The actress is also the mother of a 17-year-old daughter, Ava Elizabeth, and 13-year-old son, Deacon Reese, from her relationship with ex-husband Ryan Phillippe.
"We're all just trying to be the best parents we possibly can be," she said, "so I think it's always that question: Am I doing the right things? Am I exposing them to the right things? Am I disciplining the right way?" Check out the video below to hear more.