An interrogative pronoun (also known simply as an interrogative) is a pronoun used in asking questions. The interrogative pronouns of English are:

• Adjectival:
  • 'which', used to ask for a choice out of a known number of choices; or
  • 'what', used for one out of a large or infinite number of choices
• Person: 'who', 'whom', 'whose', 'whoever', 'whosoever', 'whomever', 'whomsoever', 'whosever'
• Thing: 'what', 'wherein', 'whereof',
• Place: 'where', 'whence', 'wherefrom', 'whither', 'whereon', 'wherever'
• Time: 'when'
• Means: 'how'
• Reason: 'why', 'how come'
• Purpose: 'wherefore', 'what for', 'whereto', 'whereunto' (see final clauses)

In English, many interrogative pronouns can also be used as relative pronouns.