The Fast of Gedalia ( /ɡɛdəˈlaɪ.ə/ or /ɡɨˈdɑːljə/; Hebrew: צוֹם גְּדַלְיָּה‎ Tzom Gedalya), also spelled Gedaliah, is a Jewish fast day from dawn until dusk to lament the assassination of the righteous governor of Judah of that name, which ended Jewish rule following the destruction of the First Temple.

When the Babylonian king Nebuchadnezzar conquered Jerusalem, he killed or exiled most of its inhabitants and appointed Gedaliah, son of Achikam as governor of the now-Babylonian province of Judah. Many Jews who had fled to Moab, Ammon, Edom, and other neighboring lands returned to Judah, tended the vineyards again, and enjoyed a new respite after their earlier suffering.