Chiaki (ちあき, チアキ) is a unisex Japanese given name used mostly by females and is occasionally used as a surname.

Chiaki can be written using different kanji characters and can mean:

• 千秋, "thousand, autumn"
• 千明, "thousand, light"
• 千晶, "thousand, sparkle"
• 千晃, "thousand, clear"
• 千瑛, "thousand, crystal ball"
• 智昭, "wisdom, shining"

The name can also be written in hiragana or katakana.

• Chiaki (tarento) (千秋; born 1971), Japanese tarento
• Chiaki Hayashi (林 千晶), Japanese businesswoman
• Chiaki Ishibashi (石橋 千彰, born 1991), Japanese swimmer
• Chiaki Ishikawa (智晶; born 1969), Japanese singer
• Chiaki Ishioka (石岡 千秋, born 1961), Japanese alpine skier
• Chiaki Ito (千晃; born 1987), member of the J-pop group AAA
• Chiaki J. Konaka (千昭; born 1961), Japanese writer and scenarist
• Chiaki Kawamata (千秋; born 1948), Japanese science fiction writer and critic
• Chiaki Kobayashi (小林 千晃, born 1994), Japanese voice actor
• Chiaki Kon (千秋), Japanese anime director
• Chiaki Kuriyama (千明; born 1984), Japanese actress, singer, and model
• Chiaki Kyan (ちあき; born 1986), Japanese singer
• Chiaki Matsumura (松村 千秋, born 1992), Japanese curler
• Chiaki Minamiyama (南山 千明, born 1985), Japanese women's footballer
• Chiaki Morosawa (千晶; born 1959), a Japanese anime screenwriter
• Chiaki Mukai (千秋; born 1952), Japanese doctor and astronaut
• Chiaki Ohara (千秋), Japanese pianist
• Chiaki Omigawa (千明; born 1989), Japanese voice actress
• Chiaki Satō (千亜妃; born 1988), Japanese actress and musician
• Chiaki Takahashi (actress) (たかはし 智秋, born 1977), Japanese voice actress
• Chiaki Takahashi (politician) (高橋 千秋, born 1956), Japanese politician
• Chiaki Yamada (山田 千愛, born 1966), Japanese women's footballer
• Naomi Chiaki (ちあき; born 1947), Japanese singer

• Chiaki Nagoya (千秋), a character in the manga/anime series Kamikaze Kaito Jeanne
• Chiaki Konoike (千秋), a character in the manga series Tenjho Tenge
• Chiaki Minami (千秋), a character in the manga series Minami-ke
• Chiaki Saionji, a central character in the manga series The Demon Ororon
• Chiaki Tani (千明), a character in Samurai Sentai Shinkenger
• Chiaki Mamiya, a major character in The Girl Who Leapt Through Time
• Shinichi Chiaki (千秋), a central character in Nodame Cantabile series
• Chiaki Tachibana, a character in the video game Shin Megami Tensei III: Nocturne
• Chiaki Yoshino (千秋), a male manga artist that pretends he is a female to the readers in the manga and anime series Sekaiichi Hatsukoi
• Chiaki Kurihara, a central character in the anime series Bodacious Space Pirates
• Chiaki Shinoda, a character in the anime Darker Than Black
• Chiaki Nanami (千秋) a main character in the video game Danganronpa 2: Goodbye Despair
• Chiaki Enno, a character in Zenki
• Chiaki Morisawa (千秋), a character in Rhythm game Ensemble Stars!
• Chiaki Koizumi (千秋), a character in the webcomic Rain
• Chiaki Ōgaki (千明), a character in the manga series Laid-Back Camp
• Chiaki Hoshinomori (千秋), a character in the light novel series Gamers!
• Chiaki Motomiya (元宮 チアキ), a character in video game Blue Archive