Willow Armstrong is a pseudonym for the American voice actress Lara Jill Miller, who has used this alternative name for certain anime voice-over credits. Miller, born April 20, 1967, in Allentown, Pennsylvania, has a background that includes a career on Broadway and television before transitioning into voice acting. Her use of the Willow Armstrong name appears to have been a professional choice, possibly related to union regulations or concurrent work on other projects.

As Willow Armstrong, her voice roles are primarily in English dubs of anime series and original video animations. She is known for providing the voice of Minawa Ando in the series Mahoromatic: Something More Beautiful, a role she also played in Mahoromatic: Summer Special. Another significant role under this name is Hikaru Shiina in the science fiction series Figure 17. In this production, she was part of the main English cast. Additionally, Armstrong voiced the character Ruka Essenpolka in the OVA series Idol Project.

Her work also includes other notable anime titles. Armstrong has credits for the character Haru in Beastars and Koko in Zatch Bell!. She performed the role of Hotaru in.hack//Legend of the Twilight and contributed additional voices to that series as well. Her voice can be heard as Misao Kusakabe in Lucky Star and as Matsuri in Naruto. Other credits include roles in Blood+, Ghost in the Shell: S.A.C. 2nd GIG, and Strait Jacket.

While Miller has numerous high-profile roles under her legal name, such as Hikari "Kari" Kamiya in Digimon Adventure and its sequel, the roles performed as Willow Armstrong represent a specific segment of her career in anime dubbing. These credits span a variety of genres and series, demonstrating her range as a performer in the industry.