疑问代词（Interrogative pronoun/Interrogative word）是词性的一种，在疑问句中，用来代替说话者在句子中想要询问的东西。例如谁、哪个、哪里、什么（物）等等。疑问代词根据各语言文法的不同，有放于词首或词末的。

An interrogative word or question word is a function word used to ask a question, such as what, when, where, who, whom, why, and how. They are sometimes called wh-words, because in English most of them start with wh- (compare Five Ws). They may be used in both direct questions (Where is he going?) and in indirect questions (I wonder where he is going). In English and various other languages the same forms are also used as relative pronouns in certain relative clauses (The country where he was born) and certain adverb clauses (I go where he goes).