A hacek or háček ("ˇ", pronounced HUH-check), also known as a caron, is a diacritic placed over certain letters to indicate palatalization or jotation in the orthography of some Slavic and Baltic languages. It looks similar to breve, but has a sharp tip, like an inverted circumflex (^), while breve is rounded.

The word háček means "little hook" in Czech. In Slovak it is called "mäkčeň" (i.e. "softener" or "palatalization mark"), in Slovenian"strešica" (i.e."little roof").

The use of hacek (and the acute) for Latin characters was introduced by Jan Hus in the 15th century into the Czech language and today it is also used by the Slovaks, Slovenians, Croatians, Serbs, Upper Lusatian and Lower Lusatian Sorbs, Lithuanians, Latvians and partly by the Poles. It is also often used for international transliteration.

Examples of letters with the háček/caron: