Ryo Sakazaki (Japanese: Katakana: リョウ・サカザキ; Kanji: 坂崎 亮(さかざき りょう), Hepburn: Sakazaki Ryō) is a character introduced in the 1992 fighting game Art of Fighting developed by SNK. In the Art of Fighting series, Ryo is depicted as a skilled martial artist who practices his family's fighting style, Kyokugenryu Karate (Japanese: 極限流空手), taught by his father Takuma. After his younger sister Yuri disappears, Ryo and his best friend Robert Garcia search South Town to find her, facing several opponents along the way. While the series follows Ryo's journey as a protector of those he loves, he also regularly appears in the crossover series The King of Fighters, in which he participates in fighting tournaments to promote the Kyokugenryu Karate. He also appears in alternate SNK games as an older fighter named Mr. Karate (Japanese: Mr.カラテ) influenced by his father Takuma. Additionally, he features in several manga adaptations and appears in the anime OVA adaptation of Art of Fighting.

SNK developers Hiroshi Matsumoto and Takashi Nishiyama created Ryo as a homage to Ryu from Capcom's Street Fighter series; the team that produced the first game in the franchise left Capcom to join SNK to produce other games. Ryo's inclusion in The King of Fighters series was decided immediately by the staff as the company wanted to employ characters from its other series in crossover games. SNK artist Hiroaki Hashimoto was responsible for his alter-ego Mr. Karate's design as he wanted to create a new design distinctly different from the original. Multiple voice actors have portrayed Ryo throughout his different appearances.

Video game publications have both praised and criticized Ryo's character. Although Ryo has been criticized for his similarities to the Street Fighter characters, several reviewers have praised his development in several SNK games such as his introduction in Fatal Fury Special and The King of Fighters as one of the first crossover characters. Ryo served as a model for the development of Dan Hibiki, a joke character in the Street Fighter series due to similar designs.

Ryo Sakazaki was created by Hiroshi Matsumoto and Takashi Nishiyama as an homage to the Capcom character Ryu because during the release of the game, some members from the original Street Fighter video game from Capcom moved to SNK. Artist Shinkiro has said he had no problems with designing Ryo because he related to drawing poor characters in contrast to drawing the other lead Robert Garcia whose depiction as wealthy was more of a problem. The similarities between Ryo and Ryu are addressed in the SNK vs. Capcom crossover games where they often interact.

SNK staff member Youichiro Soeda said that Ryo and Robert's debut was unique to other games based on the company because the story did not focus on fighting tournaments but instead on the duo's quest to save Yuri Sakazaki. Matsumoto has stated that Ryo's and Robert's story are appealing to people thanks to its presentation in cutscenes in contrast to other games that were given animated or printed adaptations that explored the narrative more.

In the planning stage of Fatal Fury Special, another SNK fighting game, bringing Ryo to the installment was elaborated by planner planner Yasuyuki Oda; He believes Ryo fits the cast due to how the franchise borrowed Desperation Moves from Art of Fighting and how it revolutionized the idea of the crossover concept that would conceptualize The King of Fighters. However, as Ryo was announced at the Tokyo Game Show, Oda found such an unpredicted reveal awkward; Fatal Fury Special had several issues at launch in every single console and unlocking Ryo as a hidden boss was too challenging. In some games starting from Fatal Fury: Wild Ambition, Ryo goes by the nickname of "Mr. Karate". Artist Falcoon says this was a reference to how Ryo managed to defeat his father Takuma Sakazaki and thus became worthy of that title. Writer Akihiko Ureshino originally aimed to give Ryo a bigger role in the Fatal Fury series where he would fight a revived Geese Howard but was rejected by members from editorial Shinseisha. The concept would have been villain Geese reviving and an aged Ryo settles things with him.

Ryo was first voiced by Masaki Usui. Starting in 2016 with The King of Fighters XIV, Usui was replaced by Daiki Takakura who wanted to promote his character's appearances. Takakura believes his role as Ryo is important because the character appeared on multiple generations of consoles and he wanted to keep its traditional style despite having a different voice. For the otome game, The King of Fighters: For Girls, Subaru Kimura voices the character. Alden Crews voiced Ryo in the English dub of the anime special.

The character was modeled after American actor Patrick Swayze. Often dealing with his school in Art of Fighting and The King of Fighters, by the time of Garou: Mark of the Wolves, Ryo is still in his position as the head of Kyokugen-ryu karate, and he retreats to the mountains to train. Ureshino claims the goal is not to reach the goal of being the strongest, but rather he is the type who wants to keep getting stronger, even if it is just a little at a time. As a result, Ureshino describes Ryo as a man who will find it difficult in modern society and never marries his love interest King. The developers added that The King of Fighters '94 was created with the idea of having Ryo fighting against Terry Bogard, the lead character of the Fatal Fury series. Ryo and Yuri do not tend to be unable to get involved in the main story and end up in comical roles in contrast to the more serious style from Art of Fighting. In regards to the masked Mr. Karate from the spin-off Maximum Impact 2, Ureshino decided to give him the age of 49, making him the oldest character of the title.