Ensign Helen Zilwicki is a fictional character in the Honorverse, a series of military science fiction novels written by David Weber.

She is the daughter of Captain Anton Zilwicki and the late Captain Helen Zilwicki. Her adopted siblings are Berry Zilwicki and Larens ("Lars") Zilwicki. Her de facto stepmother is Catherine Montaigne, former Countess of the Tor.

Helen's first appearance was as a 4-year old girl in The Short Victorious War, when her mother sacrificed herself and her ship to protect the convoy Helen and Anton were escaping in. Helen Sr was posthumously awarded the Parliamentary Medal of Valor (the Manticoran equivalent of a Victoria Cross or the Medal of Honor).

She subsequently appeared at age 14 in From the Highlands. She was kidnapped and held for ransom by slavers in the catacombs under Chicago. An expert in Neue-Stil Handgemenge, she killed three men barehanded after escaping, and saved the lives of Berry and Lars.

Helen also appeared in War of Honor where she was attending the Saganami Naval Academy.

She had a brief appearance in Crown of Slaves, a book which mostly concerned Anton and Berry's adventures on Erewhon and Torch.

The Shadow of Saganami had Helen as a major character. She served as a Midshipwoman (an Honorverse variant of Midshipman) aboard the heavy cruiser HMS Hexapuma, under the command of Captain Aivars Terekhov. Her Officer Candidate Training Officer was Lieutenant (junior grade) Abigail Hearns. She developed a romantic interest in Paulo d'Arezzo, a fellow midshipman.

She is effectively Crown Princess (Heiress Presumptive) of Torch according to the Torch constitution. She is the oldest sibling of her sister Queen Berry, who currently has no children.