'The King In Yellow' can refer to several things:
- The Book by Robert W. Chambers – this is the volume of real-world fiction that inspired the many imitators who have contributed to the Yellow Mythos. Some later stories accept that Chambers' work exists within the fictional world of the Mythos.
- The Play – a fictional drama invented by Chambers and mentioned several times in his fiction.
- Other Fictional Plays – some stories incorporate 'forged versions' of the fictional play.
- Reconstructions of the Play – some authors have used the brief hints dropped by Chambers in his writing to try to write a complete text of the imagined play. Two versions published under the actual title of the play (as opposed to within a wider story) are The King In Yellow: A Tragedy in Verse by Lin Carter, and The King In Yellow by Thom Ryng.
- The King in Yellow himself; or perhaps, rather, itself – a largely unseen character within the fictional play (and appearing elsewhere within the mythos), often assumed to be a powerful, god-like being.
- Other uses of the title have appeared in fiction that do not directly connect to the Mythos.