Greek Extended is a Unicode block containing the accented vowels necessary for writing polytonic Greek. The regular, unaccented Greek characters as well as the characters with tonos and diaeresis can be found in the Greek and Coptic block. Greek Extended was encoded in version 1.1 of the Unicode Standard. As an alternative to Greek Extended, combining characters can be used to represent the tones and breath marks of polytonic Greek.

This article contains Greek text. Without proper rendering support, you may see question marks or boxes, misplaced vowels or missing conjuncts instead of Greek letters.

In this block, the letters with oxia (acute accent) and no other accent are not used in any of the Unicode normalizations. Decomposition of U+1F71 ά GREEK SMALL LETTER ALPHA WITH OXIA, for example, yields U+03B1 α GREEK SMALL LETTER ALPHA followed by a U+0301 ◌́ COMBINING ACUTE ACCENT, while composition yields the same letter with tonos, U+03AC ά GREEK SMALL LETTER ALPHA WITH TONOS, from the Greek and Coptic block.

The following Unicode-related documents record the purpose and process of defining specific characters in the Greek Extended block: