

Third interval may refer to one of the following musical intervals in equal-temperament tuning:
Alternatively, it may apply to
| Number of semitones | Minor, major, or perfect intervals | Short | Augmented or diminished intervals | Short | Short | Audio | ||
|---|---|---|---|---|---|---|---|---|
| 2 | M2 | Diminished third | d3 | Tone, whole tone, whole step[1] | T | |||
| 3 | Minor third | m3 | A2 | |||||
| 4 | Major third | M3 | d4 | |||||
| 5 | P4 | Augmented third | A3 |