A close vowel is a type of vowel sound used in many spoken languages. The defining characteristic of a close vowel is that the tongue is positioned as close as possible to the roof of the mouth without creating a constriction that would be classified as a consonant. Close vowels are often referred to as high vowels because the tongue is positioned high in the mouth during the articulation of a close vowel.

The close vowels identified the International Phonetic Alphabet are:

• close front unrounded vowel [ i]
• close front rounded vowel [ y]
• close central unrounded vowel [ ɨ]
• close central rounded vowel [ ʉ]
• close back unrounded vowel [ ɯ]
• close back rounded vowel [ u]

In the context of the phonetics of any particular language, a high vowel can be any vowel that is more close than a mid vowel. That is, close-mid vowels, near-close vowels, and close vowels can all be considered high vowels.