Alexandra "Alex" Udinov is a fictional character on the American television series Nikita, portrayed by Lyndsy Fonseca.

Nikita saves Alex and kills her father, and she watches the rest of her family perish in a fire.

Alex brings this part of her past up to Amanda, saying that the slavers "had the decency to keep [her] high" as they held her captive, comparing it to Division.

After Nikita helps Alex get past the worst part of her withdrawal, she starts to train her both mentally and physically to stay one step ahead of Division once she is inserted there.

Saving Alex is the first time Nikita defied her orders from the Division to kill her entire family.

After Alex gets sick of waiting in Division's medical bay and hurts after her and Sean's conversation, she tells Nikita that she is going on the mission to Amanda's house with her.

Amanda "brainwashes" Alex with "the chair" by forming bridges where they are not supposed to, making her irrational and mentally unstable.

Alex recruits Birkoff to dig up secrets on Danforth to use as leverage in case complications arise with the government.

They are shocked when they find out that the president has made a kill house and is ready to wipe out all of the division with the marines that are trained.

The tortured, recalcitrant junkie kid in the flashbacks could easily have been overplayed, but she handled it extremely well, showing breadth in her abilities this early on, and in the present day scenes she also gives off the unmistakeable aura of someone who is a little bit harder than they are letting on."

Gabrielle Compolongo of TV Fanatic said that "Alex plays the clueless trainee perfectly" and she does "every intelligent thing" not to be caught.