Absolute pitch (AP), often called perfect pitch, is the ability to identify or re-create a given pitch without the benefit of a reference tone. AP may be demonstrated using linguistic labelling ("naming" a note), associating mental imagery with the note, or sensorimotor responses. For example, an AP possessor can accurately reproduce a heard tone on a musical instrument without "hunting" for the correct pitch. However, pitch labelling is less common than pitch recall.

The frequency of AP in the general population is not known. A proportion of 1 in 10,000 is widely reported, but may not be accurate; a 2019 review indicated a prevalence of at least 4% amongst music students.

Generally, absolute pitch implies some or all of these abilities, achieved without a reference tone:

Absolute pitch is distinct from relative pitch. While the ability to name specific pitches can be used to infer intervals, relative pitch identifies an interval directly by its sound. Absolute pitch may complement relative pitch in musical listening and practice, but it may also influence its development.

There has been debate as to whether absolute pitch is learnable in adulthood. Adults who possess relative pitch but do not already have absolute pitch can learn "pseudo-absolute pitch" and become able to identify notes in a way that superficially resembles absolute pitch. Some people have been able to develop accurate pitch identification in adulthood through training.

Scientific studies of absolute pitch commenced in the 19th century, focusing on the phenomenon of musical pitch and methods of measuring it. It would have been difficult for the notion of absolute pitch to have formed earlier because pitch references were not consistent. For example, the note known as 'A' varied in different local or national musical traditions between what is considered as G sharp and B flat before the standardisation of the late 19th century. While the term absolute pitch, or absolute ear, was in use by the late 19th century by both British and German researchers, its application was not universal; other terms such as musical ear, absolute tone consciousness, or positive pitch referred to the same ability. The skill is not exclusively musical.

Physically and functionally, the auditory system of an absolute listener evidently does not differ from that of a non-absolute listener. Rather, "it reflects a particular ability to analyze frequency information, presumably involving high-level cortical processing." Absolute pitch is an act of cognition, needing memory of the frequency, a label for the frequency (such as "B-flat"), and exposure to the range of sound encompassed by that categorical label. Absolute pitch may be directly analogous to recognizing colors, phonemes (speech sounds), or other categorical perception of sensory stimuli. For example, most people have learned to recognize and name the color blue by the range of frequencies of the electromagnetic radiation that are perceived as light; those who have been exposed to musical notes together with their names early in life may be more likely to identify the note C. Although it was once thought that it "might be nothing more than a general human capacity whose expression is strongly biased by the level and type of exposure to music that people experience in a given culture", absolute pitch may be influenced by genetic variation, possibly an autosomal dominant genetic trait.

Evidence suggests that absolute pitch sense is influenced by cultural exposure to music, especially in the familiarization of the equal-tempered C-major scale. Most of the absolute listeners that were tested in this respect identified the C-major tones more reliably and, except for B, more quickly than the five "black key" tones, which corresponds to the higher prevalence of these tones in ordinary musical experiences. One study of Dutch non-musicians also demonstrated a bias toward using C-major tones in ordinary speech, especially on syllables related to emphasis.