Fifth may refer to:

• One fifth, a quintile, or 20% of a certain amount.
• In the United States, the Fifth Amendment to the United States Constitution
• Fifth (Stargate), a robotic character in the television series Stargate SG-1
• the FIFTH programming language
• Beethoven's fifth symphony (commonly referred to as 'The Fifth')
• Fifth (Soft Machine album)
• A term for 750 ml or one fifth of a gallon of hard liqour
• A political term, Fifth column

• A musical interval; specifically, a perfect fifth, diminished fifth or augmented fifth
• A chord member separated from the chord's root by one of the above intervals
• The dominant or fifth diatonic scale degree, and the chord built on it.