Americanist phonetic notation, also known as the North American Phonetic Alphabet (NAPA), the Americanist Phonetic Alphabet or the American Phonetic Alphabet (APA), is a system of phonetic notation originally developed by European and American anthropologists and language scientists (many of whom were Neogrammarians) for the phonetic and phonemic transcription of indigenous languages of the Americas and for languages of Europe. It is still commonly used by linguists working on, among others, Slavic, Uralic, Semitic languages and for the languages of the Caucasus, of India, and of much of Africa; however, Uralicists commonly use a variant known as the Uralic Phonetic Alphabet.

Despite its name, NAPA has always been widely used outside the Americas. For example, a version of it is the standard for the transcription of Arabic in articles published in the Zeitschrift der Deutschen Morgenländischen Gesellschaft, the journal of the German Oriental Society.

Diacritics are more widely used in Americanist notation than in the International Phonetic Alphabet (IPA), which seeks to use as few diacritics as possible for phonemic distinctions, retaining them only for the dental–alveolar distinction. Americanist notation relies on diacritics to distinguish many other distinctions that are phonemic in the languages it transcribes. On the other hand, Americanist notation uses single letters for most coronal affricates, whereas the IPA requires digraphs. Otherwise Americanist notation has grown increasingly similar to IPA, and has abandoned many of the more obscure letters it once employed.

Certain symbols in NAPA were once identical to those of the International Phonetic Alphabet, but have become obsolete in the latter, such as ⟨ι⟩. Over the years, NAPA has drawn closer to the IPA. This can be seen, for example, in a comparison of Edward Sapir's earlier and later works. However, there remain significant differences. Among these are:

John Wesley Powell used an early set of phonetic symbols in his publications (particularly Powell 1880) on American language families, although he chose symbols which had their origins in work by other phoneticians and American writers (e.g., Pickering 1820; Cass 1821a, 1821b; Hale 1846; Lepsius 1855, 1863; Gibbs 1861; and Powell 1877). The influential anthropologist Franz Boas used a somewhat different set of symbols (Boas 1911). In 1916, a publication by the American Anthropological Society greatly expanded upon Boas's alphabet. This same alphabet was discussed and modified in articles by Bloomfield & Bolling (1927) and Herzog et al. (1934). The Americanist notation may be seen in the journals American Anthropologist, International Journal of American Linguistics, and Language. Useful sources explaining the symbols – some with comparisons of the alphabets used at different times – are Campbell (1997:xii-xiii), Goddard (1996:10–16), Langacker (1972:xiii-vi), Mithun (1999:xiii-xv), and Odden (2005).

It is often useful to compare the Americanist tradition with another widespread tradition, the International Phonetic Alphabet (IPA). Americanist phonetic notation does not require a strict harmony among character styles: letters from the Greek and Latin alphabets are used side-by-side. Another contrasting feature is that, to represent some of the same sounds, the Americanist tradition relies heavily on letters modified with diacritics; whereas the IPA, which reserves diacritics for other specific uses, gave Greek and Latin letters new shapes. These differing approaches reflect the traditions' differing philosophies. The Americanist linguists were interested in a phonetic notation that could be easily created from typefaces of existing orthographies. This was seen as more practical and more cost-efficient, as many of the characters chosen already existed in Greek and East European orthographies.

Abercrombie (1991:44–45) recounts the following concerning the Americanist tradition:

In America phonetic notation has had a curious history. Bloomfield used IPA notation in his early book An Introduction to the Study of Language, 1914, and in the English edition of his more famous Language, 1935. But since then, a strange hostility has been shown by many American linguists to IPA notation, especially to certain of its symbols.