Nao Iwamoto is a Japanese manga artist recognized for works that often blend fantasy, romance, and elements of everyday life. She made her professional debut after receiving the 10th Monthly Flowers Comic Audition Golden Flower Award for Sono Kanojo no Sonzai, which was published in the May 2004 issue of Monthly Flowers. Her early career included the serialization of works such as the short story collection Skeleton in the Closet and the one-volume series Yesterday, Yes a Day.

A significant critical milestone came with Machi de Uwasa no Tengu no Ko, which was serialized in Shogakukan's Flowers magazine. This series earned her the 55th Shogakukan Manga Award in the shōjo category in 2009, establishing her as a prominent voice in the demographic. Her work often reflects a connection to rural settings; she has noted an affinity for drawing stories in familiar, countryside environments, sometimes modeling locations on her own upbringing.

Iwamoto is the original creator behind Kin no Kuni Mizu no Kuni, also known as Gold Kingdom and Water Kingdom. This romantic fantasy manga was serialized in Flowers from October 2014 to April 2016, with its chapters compiled into a single volume published by Shogakukan in July 2016. The series achieved significant recognition, topping the Kono Manga ga Sugoi! list for female readers in 2017 and ranking second in the Manga Taishō awards the same year. The story centers on two feuding kingdoms where a princess and an architect enter a pretend marriage to secure peace, only to find genuine affection. The manga was adapted into an anime film produced by Madhouse, which premiered in Japanese theaters in January 2023. A subsequent English-language edition of the manga was released by Seven Seas Entertainment in November 2023.

Following the success of that work, she began serializing Marronnier Oukoku no Shichinin no Kishi, known in English as Seven Knights of the Marronnier Kingdom. This ongoing series, which started in 2016, further demonstrates her focus on elaborate fantasy worlds. Her artistic approach has evolved over time; while her earlier works were frequently grounded in contemporary rural Japan, she began creating more historically-set fantasy narratives starting around 2014, a genre shift she had long been interested in pursuing.

Her creative process and career were the subject of an episode of the documentary series Manben, hosted by Naoki Urasawa. The episode, which originally aired in Japan in October 2020, documented her as she worked on pages for Seven Knights of the Marronnier Kingdom. An illustration collection commemorating her 15th debut anniversary was published in 2019. In October and November 2021, her first solo exhibition was held at the Yoshibigawa Kami Exchange Manga Art Museum in Okayama Prefecture, her birthplace.