In law, interrogatories are a formal set of written questions propounded by one litigant and required to be answered by an adversary, in order to clarify matters of evidence and help to determine in advance what facts will be presented at any trial in the case.

The vast majority of such questions are to find background information about the litigants that is not specific to each case, so it is common to use pre-printed forms containing standard questions that are generally relevant to the type of case at hand, called form interrogatories. These may even be determined by statute or court rules.