Mediator may refer to:

• A neutral party who assists in negotiations and conflict resolution, the process being known as mediation
• Mediator variable in statistics
• The Mediator pattern in computer science
• The multiprotein Mediator (coactivator) in Molecular Biology functions as a transcriptional coactivator
• Mediator (software), an advanced multimedia authoring tool for Windows
• Guitar pick or plectrum, an accessory that assists picking strings of musical instruments
• Mediator is an 18th century card game.
• The Mediator, a teen book series by Meg Cabot (some under the pseudonym Jenny Carroll )
• Christ as Mediator
• Benfluorex, an antiobesity drug sold under the name "Mediator"