Last week, the former Playboy playmate admitted she was very anxious about the diving competition, but she made it through the first round of the show.
However, during Tuesday's episode she pulled out of her routine, which involved jumping from a 23-foot-high platform.
She explained to her fellow competitors and the audience: "I'm so sorry, everybody. This is the first time in my life I've quit something. This will haunt me for the rest of my life."
She later added on Twitter, "Damn I got a lot of hate tonight but ill take it. Big mistake signing up for the show. Sorry I let you all down."
Wilkinson is most known for being one of Hugh Hefner's former girlfriends and starring in the E! reality series "The Girls Next Door" with the Playboy mogul's other girlfriends - Holly Madison and Bridget Marquadt.
She later married former football star Hank Baskett, and they have a son together.