A pitch-accent language is a type of language that, when spoken, has certain syllables in words or morphemes that are prominent, as indicated by a distinct contrasting pitch (linguistic tone) rather than by volume or length, as in some other languages like English. Pitch-accent languages also contrast with fully tonal languages like Vietnamese, Thai and Standard Chinese, in which practically every syllable can have an independent tone. Some scholars have claimed that the term "pitch accent" is not coherently defined and that pitch-accent languages are just a sub-category of tonal languages in general.

Languages that have been described as pitch-accent languages include: most dialects of Serbo-Croatian, Slovene, Baltic languages, Ancient Greek, Vedic Sanskrit, Tlingit, Turkish, Japanese, Limburgish, Norwegian, Swedish of Sweden, Western Basque, Yaqui, certain dialects of Korean, Shanghainese, and Livonian.

Pitch-accent languages tend to fall into two categories: those with a single pitch-contour (for example, high, or high–low) on the accented syllable, such as Tokyo Japanese, Western Basque, or Persian; and those in which more than one pitch-contour can occur on the accented syllable, such as Punjabi, Swedish, or Serbo-Croatian. In this latter kind, the accented syllable is also often stressed another way.

Some of the languages considered pitch-accent languages, in addition to accented words, also have accentless words (e.g., Japanese and Western Basque); in others all major words are accented (e.g., Blackfoot and Barasana).

The term "pitch accent" is also used to denote a different feature, namely the use of pitch when speaking to give selective prominence (accent) to a syllable or mora within a phrase.

Scholars give various definitions of a pitch-accent language. A typical definition is as follows: "Pitch-accent systems [are] systems in which one syllable is more prominent than the other syllables in the same word, a prominence that is achieved by means of pitch" (Zanten & Dol 2010, p. 120). That is to say, in a pitch-accent language, in order to indicate how a word is pronounced it is necessary, as with a stress-accent language, to mark only one syllable in a word as accented, not specify the tone of every syllable. This feature of having only one prominent syllable in a word or morpheme is known as culminativity.

Another property suggested for pitch-accent languages to distinguish them from stress languages is that "Pitch accent languages must satisfy the criterion of having invariant tonal contours on accented syllables ... This is not so for pure stress languages, where the tonal contours of stressed syllables can vary freely" (Hayes 1995, p. 50). Although this is true of many pitch-accent languages, there are others, such as the Franconian dialects, in which the contours vary, for example between declarative and interrogative sentences.

According to another proposal, pitch-accent languages can only use F0 (i.e., pitch) to mark the accented syllable, whereas stress languages may also use duration and intensity (Beckman 1986). However, other scholars disagree, and find that intensity and duration can also play a part in the accent of pitch-accent languages (Levi 2005).