To me, sentences that start with "Guess" are in the imperative mood, thus, should end with a period:

  • Guess who's coming to town.
  • Guess what we had for dinner last night.

Why do a lot of publications put a question mark at the end of these sentences? I've been taught that you put a question mark only if the sentence is in the interrogative "mood". In these cases, we're not asking who's coming to town or what we had for dinner last night - we know who's coming and what we ate. We're telling that second person to guess.

If "Guess _ ?" is correct because it expects an answer just like a regular question, is it acceptable, then, to write:

  • Tell me who's coming to town?
  • Tell me what I had for dinner last night because I forgot?

"Tell __ ?" looks just as unsettling to me as "Guess _?".

  • 48
    Shouldn’t that be "Guess why this sentence ends in a question mark?"
    – l0b0
    Commented Sep 9, 2014 at 8:43
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    Consider that a guess wh- sentence can be said in two ways: as an actual imperative, and as a kind of hortative question-like utterance. “Guess what I’ve got in my pocket? [You’re gonna like it!]” is quite different, both in inflection and in pragmatic meaning, from “Guess what I’ve got in my pocket! [I’m not going to let you leave if you don’t guess right!]”. The intention behind the former is not to give an order; it is a pseudo-imperative at best. The intention behind the latter, on the other hand, is a clear-cut imperative. (Also, English does not have an interrogative mood.) Commented Sep 9, 2014 at 19:13
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    Do note that interrogative mood really does exist, along with indicative mood, imperative mood and subjunctive mood.* You don't need quotes. (*Subjunctive is convenient but not universally accepted)
    – Andrew Leach
    Commented Sep 9, 2014 at 21:21
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    A question mark makes this sound friendly whereas a full stop would be an order, maybe at gun point.
    – Sammaye
    Commented Sep 10, 2014 at 11:36
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    I love how this site tends to generate Famous Questions that make me first think "Well isn't that obvious?" followed by the second thought of and feeling of a bit of confusion. Good question and I can't wait to read all all of the responses below.
    – RLH
    Commented Sep 10, 2014 at 11:37

13 Answers 13


Because you have been taught an oversimplification.

Most English speakers would have no idea what you were talking about if you mentioned the "interrogative mood". People put a question mark on the end if it feels like a question.

Conversely, a polite order like

Would you sit down.

or a less polite one like

Will you sit down!

are often written without question marks, because although syntactically they have the form of questions, they are not in fact questions at all.

  • 7
    You've gone the right direction in your answer, but I think you should elaborate on what it means to "feel like a question." You might even mention other questions that appear to be imperatives, like "You washed the dishes?"
    – trlkly
    Commented Sep 10, 2014 at 4:28
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    Same with pseudo-questions like Why not shop at Waitrose today, common in England (without question marks); perhaps you can add this as another example. Commented Sep 10, 2014 at 16:54
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    I guess it all comes down to what it feels like?
    – OJFord
    Commented Sep 10, 2014 at 21:34
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    I also guess it all comes down to what it feels like.
    – rthbound
    Commented Sep 11, 2014 at 21:42
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    @ejay he's demonstrating the way punctuation changes how each sentence reads. Commented Sep 12, 2014 at 12:41

There are two ways of using those sentences. One is the literal imperative, but the other is an informal form of the question "Can you guess....". The latter version is, in fact, often spoken with a rising inflection at the end, and is understood as an invitation/query rather than a command.

I'd say that the question mark is, in fact, an indication that the speaker intended the second usage.

  • If I'm intending to ask the user to guess, I will start with "can you guess." It still seems funny to me - Guess wh- .... ?. <-- SMH. Commented Sep 9, 2014 at 21:14
  • Local usage variation, I guess. De gustibus.
    – keshlam
    Commented Sep 9, 2014 at 21:17
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    @MickaelCaruso But that you personally avoid that kind of construction isn't really relevant when you ask why others use it, is it? (I almost elided "is it" before the question mark, but that felt too cheeky.) Commented Sep 10, 2014 at 6:30
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    The answer to "Can you guess...?" is "Yes (I can guess.)" Commented Sep 10, 2014 at 15:14
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    @DaleWilson Only if you believe the answer to "can you help me" is also to say "yes" and take no further action.
    – keshlam
    Commented Sep 10, 2014 at 15:18

Because if a sentence starts with guess, it's often followed by an interrogative adverb (who, what, why, when, where, how, how much, ...), which starts a question.

Guess what? Guess who came?

If you can construct a sentence that starts with "guess" but is not followed by an interrogative adverb, chances are you don't need to end with a question mark.

Guess twice! Guess until you find it.

  • Where officially does it say that this is correct punctuation? To me, the imperative "guess" still wins, so a period should end the sentence. Commented Sep 9, 2014 at 14:10
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    Mickael: it's in the word interrogative adverb. See wiktionary: English adverbs that indicate questions, questions tend to end with a question mark. But I can see the logic behind your reasoning as well, I wouldn't mark 'Guess what I found today!' wrong.
    – Konerak
    Commented Sep 9, 2014 at 15:28
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    @MickaelCaruso: "Where officially does it say that this is correct punctuation?" -- what sort of answer are you expecting to that, an ISO standard for English punctuation? You originally asked why people do it, and you've been given reasons. If you also want references to authoritative style guides that "bless" this common practice, that's a subtly different question. Commented Sep 10, 2014 at 10:52
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    "Who" is used the same way in "Guess who came?" as in "I don't know. Tell me who came.", and in that, it's clear that there should be no question mark. It's not an interrogative adverb, it's just a relative pronoun, which has no effect on whether the full sentence is a question.
    – hvd
    Commented Sep 10, 2014 at 11:19
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    @MickaelCaruso The only reason "Tell me who came?" seems even slightly wrong is because I wouldn't expect your tone to change at the end of that sentence.
    – DCShannon
    Commented Sep 11, 2014 at 22:13

This is not an issue of grammar as the question supposes, it's an issue of orthography, or

the methodology of writing a language. It includes rules of spelling, hyphenation, capitalization, word breaks, emphasis, and punctuation.

Because orthography is inherently conventional, and the point of orthography is to encode in writing the original spoken-language construct as clearly as possible without undue complication, representing grammar is rarely its most important job. Indeed, when the grammar is unambiguous from the unpunctuated words, conveying the grammar is not what the punctuation is doing at all. In the case of terminal punctuation like the full stop, exclamation mark, and question mark, they never encode grammatical information other than sentence boundaries, and for that grammatical job they're interchangeable. So what are they actually for?

In this case, it is the convention to end these particular kinds of sentences with a question mark, regardless of whether they are actually questions or not. It's just how the language is written; consider it a matter of art and poetry, if you will. As a colour in the artist's palette, rare punctuation rules and other orthographic tools can be used to convey information above and beyond the grammar, such as intended tone of voice, or pragmatic information such as that the utterance is rhetorical.


You are taking a prescriptive approach to the rules of language. Many of us do not.

If you said "Guess who's coming to town" you would expect an answer. Therefore you have posed a question. Take the linguistic world as it is and disregard the preconceived ideas about how it ought to be.

In this view of the world the rules mentioned do not matter. One can always choose a prescriptivist approach if one wishes, but be prepared for frustration. As language evolves the rules change no matter how much the grammar police protest!

  • 3
    If you say "Tell me your name", you expect an answer. Does that mean that it's a question and should therefore end with a question mark: "Tell me your name?"
    – JLRishe
    Commented Sep 11, 2014 at 7:40
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    Actually, I wouldn't expect an answer. "Guess who's coming to town" is most frequently followed by "Who?" It is the person who is saying "guess who" who most often provides the answer, not the person they are "asking." To put it another way, we don't put a question mark after "Knock knock," but we do after "Who's there?" Commented Sep 11, 2014 at 17:30

Because "Guess who is coming?" is usually actually a lazy "(Can you) guess who is coming?"

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    Not necess-celery. More than one horror/action novel has this sort of line as a command. Commented Sep 9, 2014 at 13:59
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    @CarlWitthoft most of the thyme those would be written "GUESS WHO IS COMING!" Commented Sep 9, 2014 at 14:06
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    Why all those torte-ured puns? o.O
    – Timwi
    Commented Sep 11, 2014 at 12:35

What happened? is a question. Guess what happened! Is not strictly a question. But it is an idiomatic expression that is really an informal way of asking "Do you know what happened?" The usual responses are "in the form, "I don't know, what happened?" or "I know! I already saw the new iPhone and it's an ugly monster!"

As an editor, I would not consider a question mark at the end of a "guess what" sentence wrong -- unless it was fiction, and the character was clearly making an exclamation, not asking a question.


It's phrased as a question which anticipates an answer. In American lingo the sentence would be asked with a distinct elevation in pitch similar to any other question.

Certain regions of the US have a tendency to make all spoken statements sound like questions, a phenomenon known as "up-speak." More women than men use that vocal technique.

  • 3
    Funnily enough if I were to say "Guess who's coming?" or "Can you guess who's coming?" I would not use the same intonation for the "coming". The former I would either leave flat or drop. I'm Australian though so find American intonation odd. In Australia we use intonation a lot for emphasis.
    – kjbartel
    Commented Sep 10, 2014 at 8:52
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    I would disagree that Americans typically use question-like intonation in "Guess ..." sentences. In my experience, the emphasis is on the "Guess".
    – JLRishe
    Commented Sep 11, 2014 at 7:46
  • The wikipedia article on up-talk: en.wikipedia.org/wiki/High_rising_terminal
    – user65692
    Commented Sep 11, 2014 at 16:17

You're correct. Guess is usually an imperative verb and a sentence using it that way should not end with a question mark. The publications that do have an editor who's asleep and didn't catch the error.


Because a question mark at the end of a sentence doesn't mean "this is a question", it means "pronounce this sentence with the inflection you would use for a question".

The purpose of punctuation is to indicate the apparent mood of the speaker, it's not a part of the grammatical structure - similar to contractions; "can't" is not a word; it is a contraction, which indicates the way in which the speaker pronounced "cannot".

  • I've NEVER heard guess sentences with question inflection. Many times, the speaker is excited, so if [s]he were to write it, [s]he would put an exclamation point at the end. Commented Sep 13, 2014 at 11:52

I would say the difference is in the expected response.

The phrase, "Guess who's coming for dinner?" Could mean, "What is your guess to the question, 'Who is coming for dinner?' " A proper response would be, "um... Bob?"

The phrase, "Guess who's coming for dinner!" Could mean, "Please, ask me who is coming for dinner, because I am very excited to tell you!" In this case, a proper response would be, "Who?"

The phrase "Guess who's coming for dinner." Could mean, "You shall guess who is coming for dinner." A proper response here could be, "No, I will not guess. Tell me, or do not tell me."

In conclusion, it could be different if you are asking them to guess, telling them to guess, or just using an expression to set up an exciting statement.


A number of answers say that this is show for something like "Can you guess ....". That's possible. But another way of viewing it is that it's commanding (or requesting) the listener to make such a guess. So even though it's not literally a question, the listener is expected to respond to it as if it were.

Since it serves the same role as a question, it is often written with a question mark, or spoken with normal question inflection.


I feel most of these cases are simply resolved by using the correct punctuation. It seems to me that the confusion is relating to a missing comma in your sentences. Even when speaking such sentences there is a definitive pause between the clauses of the sentence. Tell me is a command, but the second part is a question to be answered. Here are what I feel would be more accurate punctuation:

Tell me, where are your commas?

Guess, who is coming to dinner?

Answer me, what is the point of quibbling?

  • 3
    “Guess, who is coming to dinner?” doesn’t make any sense… unless you’re speaking to someone named “Guess”.
    – Ry-
    Commented Sep 11, 2014 at 19:09
  • 2
    I wouldn't be too thrown off if I saw this, as I can imagine a person speaking like that, but it's not usual to put a pause between "Guess" and "who".
    – DCShannon
    Commented Sep 11, 2014 at 22:17
  • At this point it seems like you should be using a semicolon but I wouldn't recommend it with either.
    – Casey
    Commented Sep 12, 2014 at 18:18

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