Yukito Ayatsuji (綾辻 行人, Ayatsuji Yukito, December 23, 1960) is a Japanese writer of horror and mystery born in Kyoto, Kyoto prefecture. His birth name is Naoyuki Uchida (内田 直行, Uchida Naoyuki). He has a master degree in Education (Kyoto University). His wife is also the novelist Fuyumi Ono (小野 不由美), an writer of fantasy and horror known for her fantasy series The Twelve Kingdoms.

His representative works include the Mansion Murders series and Another. He is one of the founders of the Honkaku Mystery Writers Club of Japan.