A complex question, trick question, multiple question, fallacy of presupposition, or plurium interrogationum (Latin, 'of many questions') is a question that has a presupposition that is complex. The presupposition is a proposition that is presumed to be acceptable to the respondent when the question is asked. The respondent becomes committed to this proposition when they give any direct answer. When a presupposition includes an admission of wrongdoing, it is called a "loaded question" and is a form of entrapment in legal trials or debates. The presupposition is called "complex" if it is a conjunctive proposition, a disjunctive proposition, or a conditional proposition. It could also be another type of proposition that contains some logical connective in a way that makes it have several parts that are component propositions.

Complex questions can but do not have to be fallacious, as in being an informal fallacy.