Naofumi Iwatani (Japanese: 岩谷 尚文, Hepburn: Iwatani Naofumi) is a fictional character from the light novel The Rising of the Shield Hero written by Aneko Yusagi and illustrated by Seria Minami. Naofumi is a young man summoned into a parallel world along with three other young men to become the world's Cardinal Heroes and fight inter-dimensional hordes of monsters called Waves. Equipped with the Legendary Shield, the character earns the title of "Shield Hero" (盾の勇者, Tate no Yuusha) and goes on a journey with hatred towards society after being falsely accused of sexually assaulting a princess.

Naofumi was written by Aneko Yusagi to be a character affected by morality and how he forges bonds with other characters to recover himself from the presented crime. The anime staff aimed to portray him carefully when dealing with the character's relationships, most notably Raphtalia. He is voiced by Kaito Ishikawa in Japanese. In the English dub, he was voiced by Billy Kametz (season 1) and Steve Fu (season 2–present).

While reception of the character has been mixed based on his dark traits, multiple critics enjoyed his character arc presented in the story, most notably when dealing with his slave Raphtalia as the two grow close despite Naofumi's initial characterization. Kametz's voice acting earned him an award from Crunchyroll.

Naofumi was created by Aneko Yusagi. Yusagi stressed the importance of leading with one's morality and the idea of negative effects or impacts on other people in the making of the character as Naofumi is accused of sex abuse. Naofumi was written to come across as a composed otaku, but Yusagi believes he is stronger in the anime to the point he believes that Naofumi is seen from Raphtalia's point of view. Throughout the first chapters Naofumi is comforted by Raphtalia, which Yusagi felt was one of the best adapted parts of the anime. Another important relationship Naofumi forges in the narrative is with L'arc Berg, who is made to act like his older brother despite often irritating him.

Anime director Takao Abo aimed to portray him as the weakest of the summoned heroes due to his relative lack of aid when fighting. Screenwriter Keigo Koyanagi described these hardships as common in the isekai genre but described Naofumi as a different type of protagonist, aiming to make him come across as unique. Producer Junichiro Tamura elaborated on these difficulties and specified that ones Naofumi has to face involve unspecified dark areas as a more realistic hero. The anime staff elaborated on the difficulties of dealing with adapting the parts of the light novel when Naofumi buys Raphtalia as a slave, reminding the audience that since the character is aware he is hated by society, having a slave would not affect his popularity. Abo considers Naofumi's growthing relationship with Raphtalia and the rest of his allies as the concept of a family-like story he wanted to make.

In regards to his fighting abilities, Naofumi was found interesting by the anime staff for how his only weapon is a shield and thus he has to rely on tactics as well as Raphtalia to fight. In order to make combat more appealing, the shield was animated to have multiple forms. The staff found it challenging to properly adapt the light novel's details about Naofumi's weapon.

In the anime version, Naofumi is voiced by Kaito Ishikawa who expressed shock at how Myne falsely accused him of having assaulted her. Nevertheless, Ishikawa tried to give the character a more positive tone in order to contrast his poor state, and especially when the protagonist trains to become a stronger fighter. As a result of his brooding personality, Ishikawa tries having a mind in regards to Naofumi to portray him properly. Furthermore, when exploring Naofumi taking care of Raphtalia, the actor realized his character displayed a more charming personality. Nevertheless, he states that while he often does nice actions, he is unwilling to be open to himself and still pretends to act coldly. In the English dub of the series, Naofumi is voiced by Billy Kametz for the first season. After Kametz announced that he was taking a leave of absence from voice acting after being diagnosed with stage IV colon cancer, which ultimately led to his death on June 9, 2022, Stephen Fu replaced him for the ongoing seasons.

Naofumi is a university student who was summoned from another world after finding a book about the Four Heroes. Originally an open minded person, he becomes cynical and distrustful of others due to being looked down by his fellow heroes, subjected to religious prejudice from citizens, and being robbed and falsely accused of attempted rape by Malty. It is only after Raphtalia defended him and proclaimed her loyalty that Naofumi began to slowly open up to those around him and realizing his mistakes. Viewing his role as a Hero burdensome, having been summoned against his will, Naofumi shows little remorse in using underhanded tactics to ensure the survival of his party despite the criticism of his fellow heroes. Generally reluctant to trust strangers, often asking to be paid upfront or using slave curses to prevent lying, he tries his best to live up to the expectations of those who have placed their faith in him or treat him as an equal.