| Vo | |
| Letter: | Ո ո |
| Script: | Armenian script |
| Type: | Alphabet |
| Typedesc: | ic |
| Language: | Armenian language |
| Phonemes: | [{{IPAlink|ɔ}}] [vɔ] |
| Unicode: | U+0548, U+0578 |
| Alphanumber: | 24 |
| Number: | 600 |
| Usageperiod: | 405 to present |
| Direction: | Left-to-Right |
Vo (majuscule: Ո; minuscule: ո; Armenian: վո, վօ) is the twenty-fourth letter of the Armenian alphabet. It has a numerical value of 600.[1] It was created by Mesrop Mashtots in the 5th century AD. It represents the open-mid back rounded vowel (pronounced as //ɔ//), but when it occurs isolated or word-initially, it represents pronounced as //vɔ//. It is one of the two letters that represent the sound O, the other being Օ which was not created by Mashtots.
Its minuscule variant is homoglyphic to the minuscule form of the Latin letter N. In its uppercase form, it looks like a turned Latin letter U, the Lisu letter Ue (ꓵ), or the asomtavruli form of the Georgian letter ghani (Ⴖ).
This letter, along with Vyun (or Hiwn in Classical Armenian), is part of the Armenian U (ՈՒ Ու ու). Because the letter U is not present in Mashtots's alphabet, it uses a digraph made up of these letters.