Jill is one of the girls who is/are missing.

[kohyoongliat]

Jill is one of the girls who is/are missing.

Which is the correct verb?

Thanks.

[Rover_KE]

A case can be made for both options.

***

I have changed your thread title.

'Thread titles should include all or part of the word/phrase being discussed.'

[emsr2d2]

Use "is" if you take "who" to refer to Jill. Use "are" if you take "who" to refer to the missing girls.

[jutfrank]

My instant interpretation was that there are multiple missing girls, so are.

I think it's very unlikely to be meant in the other way. In fact, I think it barely makes any sense at all. Do other members not agree?

kohyoongliat, please tell us where you got this sentence.

[GoesStation]

I agree.

[Yankee]

I have to go with "is". Remove "of the girls".

[Raymott]

A simple reordering gives "Of the girls who are missing, one is Jill". "are" sounds most natural and grammatical to me.
In both cases, you already have an "is" for Jill.

[Raymott]

I have to go with "is". Remove "of the girls".

Yes, if you delete the phrase that requires "are", it's easy to make the case for not using "are". But "Jill is one who is missing" is not the sentence.

[Phaedrus]

A simple reordering gives "Of the girls who are missing, one is Jill". "are" sounds most natural and grammatical to me.
In both cases, you already have an "is" for Jill.

A reordering can be given for either parsing, actually, along with different contexts:

(1) Jill is one of the girls who are missing. Indeed, she has been one of the missing girls for quite some time.
Of the girls who are missing, one is Jill.

(2) Jill is one of the girls who is missing. Others of the girls are missing, too, though you are right that not all of them are.
Of the girls, Jill is one who is missing.

"One" would naturally be emphasized in interpretation (2), as would "others" in the second, contextualizing sentence of (2).

Attached are two old-fashioned Reed–Kellogg diagrams, one for the parsing with "who are" and the other for the parsing with "who is."

[PaulMatthews]

Jill is one of the girls who is/are missing. Which is the correct verb?

[1] Jill is one of the girls who is/are missing.

[2] Jill is one of the girls who is/are missing.

The question here is whether the underlined relative clause belongs in the embedded noun phrase (with "girls" as head), as in [1], or the upper one (with "one" as fused determiner-head), as in [2]

The natural interpretation is that the relative clause modifies "girls": there is a set of girls who are missing and "Jill" is a member of this set.

However, you may well come across singular override, as in

[3] Jill is one of the girls who is/are missing.

which presumably can be attributed to the salience within the whole structure of singular "one". But it cannot be regarded as a semantically motivated override: semantically the relative clause modifies "girls".