Nessarose Thropp is the name of the woman who becomes the Wicked Witch of the East in Wicked: The Life and Times of the Wicked Witch of the West by Gregory Maguire, as well as in the Broadway adaptation, Wicked. She is the spoiled younger sister of Elphaba, the Wicked Witch of the West. In both the play and the novel, Elphaba is considered a pale second to her beautiful but handicapped sister. Elphaba is often expected to put the needs of her sister before her own. In the novel, Nessarose and Elphaba have a younger brother named Shell.

Nessarose, during her rule of Munchkinland, is dubbed "The Wicked Witch of the East", for her cruel ways and use of sorcery to control her subjects. In both the musical and the novel, Nessarose meets her demise when Dorothy's house lands in Oz and crushes her.

In Maguire's novel, Nessarose is a very pious and religious character. She was born without arms, presumably from medicine her mother took to prevent another child with the same odd appearances as the green-skinned Elphaba. Despite her condition, she is a dainty and beautiful girl, and when attending Shiz University, she more easily gains friends than her sister. She is aided by Nanny at home. Nessarose, despite her pious religious convictions, is often close-minded and vain, in following with Maguire's cynicism throughout the novel towards religion in general. Unlike in the musical version, Nessarose is not infatuated with Boq, the Munchkin boy, and lives a solitary life.

Nessarose is chosen by Madame Morrible to be an Adept – a trained sorceress, with political authority over a particular area (which was supposed to be in the South, Quadling Country). During Nessarose's reign in Munchkinland, despite her religious conviction, she allows more ancient practices to take place - including ritualistic sacrifice, rumoured to even include those of humans and Animals. Also, the book states that it may have been a spell the Nessarose cast on an axe, that backfired and turned a Woodsman into the Tin Woodsman.

Nessarose is the original owner of the magical silver shoes (most commonly known as the ruby slippers from the 1939 film The Wizard of Oz), given to her as a loving gift by her father, and later enchanted by Glinda (in the musical adaption, the bespelled shoes are Elphaba's doing). They allow Nessarose to walk and stand without assistance, and leave her overly confident and more proud, which only fuels her tyrannical reign over the Munchkins. In the novel, the shoes are a lasting symbol of Elphaba's rejection by her father, and from the world in general, and a symbol and sign of fear and later reverence by the citizens of Oz. It is Elphaba's search to retrieve Nessarose's shoes from Dorothy that causes her demise, as she becomes obsessed with obtaining the objects that have always existed as a reminder to her unusualness.

The story reveals that Nessarose may be the child of Turtle Heart, the Quadling glassblower who resided with the Thropps. Nessarose's father, Frex, confesses as much to Elphaba after Nessarose's death, adding that he and his wife Melena loved Turtle Heart equally. The implications of that statement are, however, never fully developed. It is because of the questionable parentage of Nessarose that Frex loves her more than Elphaba, as if she had been conceived more of the love between the odd trio. Nessarose dies not knowing the debate over her parentage, or that her perhaps-father Turtle Heart was viciously sacrificed, not unlike the rituals she allowed her people to conduct to appease them to her rule. (It should be noted that Turtle Heart is a Quadling, and in Baum's original novels, some Quadlings have no arms. This may be Maguire's way of affirming Nessarose's parentage for the readers without specifically stating it.)