Barred o (capital: Ɵ, lowercase: ɵ) is a letter in several Latin alphabets.
Historic examples include the Azerbaijani alphabet used between 1922 and 1933 and its successor, the Uniform Turkic Alphabet (including its versions like Jaꞑalif and the Azerbaijani alphabet used between 1933 and 1939), in which it represented the open-mid front rounded vowel [œ].
In many alphabets it was replaced by the Cyrillic letter Ө ө in 1939. In Azerbaijani, it was again replaced by the Latin letter Ö ö in 1991.
The Tatar Latin alphabet devised in the late 1990s by the Tatarstan authorities included the letter Ɵ ɵ. The letter is also part of the African reference alphabet.
In the International Phonetic Alphabet, the lowercase [ɵ] represents the close-mid central rounded vowel.
It has no relation to the slashed zero, slashed O (Ø ø), the similar Latin letter Ꝋꝋ, the Cyrillic letter fita (Ѳ), or the Greek theta (Θ θ), despite their similar shapes.
| Character || Ɵ || ɵ |
| Unicode name || LATIN CAPITAL LETTER O WITH MIDDLE TILDE || LATIN SMALL LETTER BARRED O|
| Encodings || decimal || hex || decimal || hex |
| Unicode || 415 || U+019F || 629 || U+0275 |
| UTF-8 || 198 159 || C6 9F || 201 181 || C9 B5 |
| Numeric character reference || Ɵ || Ɵ || ɵ || ɵ |