Selkup is the language of the Selkups, belonging to the Samoyedic group of the Uralic language family. It is spoken by some 1,570 people (1994 est.) in the region between the Ob and Yenisei Rivers (in Siberia). The language name Selkup comes from the Russian селькуп, based on the native name used in the Taz dialect, шӧльӄумыт әты šöľqumyt əty, lit. 'forest-man language'. Different dialects use different names.

Selkup is fractured in an extensive dialect continuum whose ends are no longer mutually intelligible. The three main varieties are the Taz (Northern) dialect (тазовский диалект, tazovsky dialekt), which became the basis of the Selkup written language in the 1930s, Tym (Central) dialect (тымский диалект, tymsky dialekt), and Ket dialect (кетский диалект, ketsky dialekt). It is not related to the Ket language.

There are 25 vowel and 16 consonant phonemes in the Taz dialect.

• Voicing is not phonemic. Stops and fricatives may be voiced between vowels or after sonorant consonants.
• The palatalized stop and fricative /tʲ/, /ʃʲ/ are most typically rendered as an alveolo-palatal affricate [tɕ] and fricative [ɕ]. Depending on the speaker, the former can be also realized as the stop [tʲ], the latter as a non-palatalized fricative, postalveolar [ʃ] or retroflex [ʂ].
• Before front vowels, palatalized variants of other consonants are also found.
• [ɴ] and [ʀ] are allophones of /q/ when occurring before nasals and liquids, respectively.
• The non-coronal stops /p/, /k/, /q/ have optional fricative allophones [f], [x], [χ] when occurring before /s/ or /ʃʲ/.

• Vowel length is phonemic. /ɔː/ alone, deriving from proto-Selkup */aː/, has no short counterpart.
• The tenseness contrast, an innovation of northern Selkup, is independent of length (e.g. /i/, /iː/, /ɪ/, /ɪː/ all contrast).
• The full range of vowel quality contrasts is only possible in the initial syllable of a word: in later syllables, /e/ /ø/ /ɘ/ /y/ /ɨ/ of either length do not occur, nor does long /uː/. (Shown on a darker gray background.)
• The non-phonemic lax central vowel [ɪ̈ ~ ə] only occurs in unstressed non-first syllables; it is normally treated equivalent with short tense /ɨ/.

Selkup has a syllable structure (C)V(C). Word-initial /ŋ/ and word-final /tʲ/ or /w/ do not occur. Various consonant clusters and geminate consonants such as /nt/, /rm/, /ʃʲʃʲ/ may occur, though many potential combinations occurring morphologically are simplified.

Stress in Selkup is marginally phonemic. Generally the rightmost long vowel in a word is stressed, or otherwise the first syllable, but certain suffixes with short vowels may acquire stress, leading to minimal pairs such as [ˈtɕɛlʲtɕalqo] 'to stamp down' vs. [tɕɛlʲˈtɕalqo] 'to stamp once'.