In grammar, a circumstantial voice, or circumstantial passive voice, is a voice that promotes an oblique argument of a verb to the role of subject; the underlying subject may then be expressed as an oblique argument.
A given language may have several circumstantial voices, each promoting a different oblique argument.
Circumstantials are conceptually similar to applicatives, which promote obliques to direct objects.
However, applicatives may increase the valency of an intransitive verb by adding a direct object, while circumstantials cannot.
Circumstantials are found in Malagasy, as well as Toba Batak.