T, or t, is the twentieth letter of the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is tee (pronounced /ˈtiː/ ^ⓘ), plural tees.

It is derived from the Semitic Taw 𐤕 of the Phoenician and Paleo-Hebrew script (Aramaic and Hebrew Taw ת/𐡕/, Syriac Taw ܬ, and Arabic ت Tāʼ) via the Greek letter τ (tau). In English, it is most commonly used to represent the voiceless alveolar plosive, a sound it also denotes in the International Phonetic Alphabet. It is the most commonly used consonant and the second-most commonly used letter in English-language texts.

Taw was the last letter of the Western Semitic and Hebrew alphabets. The sound value of Semitic Taw, the Greek alphabet Tαυ (Tau), Old Italic and Latin T has remained fairly constant, representing [t] in each of these, and it has also kept its original basic shape in most of these alphabets.

In English, ⟨t⟩ usually denotes the voiceless alveolar plosive (International Phonetic Alphabet: /t/), as in tart, tee, or ties, often with aspiration at the beginnings of words or before stressed vowels. The letter ⟨t⟩ corresponds to the affricate /t͡ʃ/ in some words as a result of yod-coalescence (for example, in words ending in -"ture", such as future).

A common digraph is ⟨th⟩, which usually represents a dental fricative, but occasionally represents /t/ (as in Thomas and thyme). The digraph ⟨ti⟩ often corresponds to the sound /ʃ/ (a voiceless palato-alveolar sibilant) word-medially when followed by a vowel, as in nation, ratio, negotiation, and Croatia.

In a few words of modern French origin, the letter T is silent at the end of a word; these include croquet and debut.

In the orthographies of other languages, ⟨t⟩ is often used for /t/, the voiceless dental plosive /t̪/, or similar sounds.

In the International Phonetic Alphabet, ⟨t⟩ denotes the voiceless alveolar plosive.