John Knightley may refer to:

• Emma#Principal characters
• John Knightley (MP) for Warwickshire (UK Parliament constituency)
• Sir John Knightley, 1st Baronet (c. 1611–c. 1670) of the Knightley Baronets
• Sir John Knightley, 2nd Baronet (d. 1689) of the Knightley Baronets
• Sir John Knightley, 1st Baronet (1747–1812) of the Knightley Baronets

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• Specificied operating temperature
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• Specific latent heat of sublimation
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• Specific learning disabilities