A with diaeresis may refer to:

• A with diaeresis (Cyrillic), a conventional name of letter , from several Cyrillic alphabets: Gagauz, Khanty, Kildin Sami and Western Mari
• , known as A with diaeresis or A with umlaut, a letter , of Latin-based German, Estonian, Finnish, Slovak, Swedish, Romani and Turkmen alphabets