A court clerk (British English clerk to the court; American English clerk of the court or clerk of court) is an officer of the court whose responsibilities include maintaining the records of a court. Another duty is to administer oaths to witnesses, jurors, and grand jurors. Traditionally, the clerk also was the custodian of the court's seal, which is used to authenticate copies of the court's orders, judgments and other records.

In common law jurisdictions, the existence of the office of a clerk is one of the typical criteria distinguishing a court of record.

He/She may be more precisely titled after the (type of) court, e.g. clerk of the peace attending to a justice of the peace, clerk of the police court, etc. On Guernsey, the medieval French term Greffe is used (in the magistrates' court).

In some jurisdictions, the court clerk is the one who reads the jury's verdict form to the court. In many states, the clerk of circuit court may officiate civil weddings.

In courts without a clerk, or if there is no specific officer otherwise available, the judge may have authority to act as clerk of the court, as sometimes in a short-staffed probate court.