727 may refer to:

• 727 BC: a year.
• 727 (AD; DCCXXVII): a year.
• 727 (number): a number.
• "727", a song by The Box Tops from the album Cry Like a Baby
• Boeing 727 (B727): an aircraft model.
• 7/27, a 2016 album by Fifth Harmony
• Area code 727, for telephones in Pinellas County, Florida
• USS Michigan (SSBN-727), a U.S. ballistic missile submarine

• Principle (chemistry)
• Principle component analysis
• Principle Component Analysis
• Principle components analysis
• Principle ideal
• Principle ideal domain
• Principle of abstraction
• Principle of Binominal Nomenclature
• Principle of Calorimetry
• Principle of causality
• Principle of Cause and Effect
• Principle of charge conservation
• Principle of complementarity
• Principle of Compositionality
• Principle of computational equivalence
• Principle of consent
• Principle of contradiction
• Principle of Correspondence
• Principle of covariance
• Principle of cross cutting relationships
• Principle of Cross Cutting Relationships
• Principle of Disclosure
• Principle of disclosure
• Principle of duality
• Principle of equal a-priori probability