Eighth is ordinal form of the number eight.

Eighth may refer to:

• One eighth, 1⁄8 or ⅛, a fraction, one of eight equal parts of a whole
• Eighth note (quaver), a musical note played for half the value of a quarter note (crotchet)
• Octave, an interval between seventh and ninth
• Eighth octave C, a C note
• Eighth Lake, a lake by Inlet, New York

• 1/8 (disambiguation)
• 8 (disambiguation)
• The 8th (disambiguation)
• The Eighth Day (disambiguation)
• All pages with titles beginning with Eighth