Blue blood may relate to:

• Hemocyanin: a blood protein in many molluscs and the arthropod horseshoe crab, whose oxygenated form is blue;
• Nobility: in the English language, blue blood is used to denote noble birth.

“Blue blood” also appears in the titles and trademarks:

• Blue Blood (album): an album by X Japan;
• Blue Blood (book): a book by Edward Conlon;
• Blue Blood (film): a film directed by Stevan Riley;
• Blue Blood (magazine): content producer, packager, and publisher which began as a magazine of counterculture erotica
• Blue Blood Denim: a Dutch brand of luxury jeans.