Endorsement (alternatively spelled "indorsement") may refer to a:

• testimonial, a written or spoken statement promoting or advertising a product
• political endorsement, publicly declaring support for a candidate
• form added to an insurance policy, to modify its terms
• signature on a negotiable instrument, such as a check
• blank endorsement, a signature given without indicating the instrument's payee
• note added to a driver's license, often to record a traffic offense

• Endorsement test, the separation between state and religion as tested by the United States Supreme Court
• Forged endorsement, a legal description of forged endorsement