This is a list of characters who appear in Bushiroad's Tantei Opera Milky Holmes franchise. The series, which takes place in the Great Detective Era where both detectives and thieves use special powers known as Toys to battle against each other, follows four young girls who form the Milky Holmes detective agency. Many of the characters are named after characters from various detective novels.
Characters introduced in ''Tantei Opera Milky Holmes''
;Kamaboko ;Buta ;Irene Adler ;Irene's Father ;Sonia Kurusu ;Ramen Shopkeeper ;Professor Moriarty ;Cherry the Artist ;Poporo Mk-II
Minor characters
;Mary Kate ;Princess Claris ;Prince Pero ;Koboten ;Arthur Conan Doyle ;Agatha Christie ;Sushi Boss ;Prison Warden ;Coron ;The Flasher ;Train Conductor ;Haruko Minami
Characters introduced in ''Futari wa Milky Holmes''
Feathers
A pair of detectives who are the protagonists of the third anime season, Futari wa Milky Holmes. ;Kazumi Tokiwa ;Alice Myojingawa
Color the Phantom
An antagonist group who appears in Futari wa Milky Holmes. ;Shion Myojingawa Violet Shadow ;Keiko Totsugawa Pink Lovely Doom ;Great White Fallen Angel Darkside Revolution ;Red Lion of the Gale ;Ryōko Komatsu Yellow Black Hole ;The Fearsome Blue Hunter
Other characters
;Visconte ;Madame Visconte ;Kazumi's Father ;La Lunar ;Monseur Miller ;Old Lady
Characters introduced in ''Tantei Kageki Milky Holmes TD''
The Elements are Marine's Toys who help form her miraculous singing voice, who became separated. ;Melodia ;Harmony ;Poemy He was found possessing Nero after a short nap on the day after she had an argument with the other members of the Milky Holmes. ;Crescendo She was found possessing Scarlet during a trip to rescue Marine and prevent Scarlet from taking the priceless gem from the sky casino. She was forced to break the bond between Scarlet and herself after Miki used her toys. ;Decrescendo She was found possessing a dealer Noir during a trip to the Scarlet's newly opened casino. ;Shout She was found possessing Sakiko Kirumiya who was a one-hit wonder idol. ;Dancing He Marima is then revealed to be possessed by another Element, Dancing, who challenges Milky Holmes to see who can best imitate a good-looking man, which Hercule manages to win due to having a sore throat. ;Rhythmic ;Amoore
Other characters
;Nobles
Characters introduced in the PSP Visual Novel Games
