The Thin Red Line is a phrase or title that refers to an outgunned military unit holding firm against attack:

• The Thin Red Line (1854 battle), the original reference to the resistance by 93rd (Highland) Regiment in the Crimean War
• The Thin Red Line , 1962 novel by James Jones about fighting on Guadalcanal
• The Thin Red Line , 1964 movie based on Jones's novel
• The Thin Red Line, 1998 movie based on Jones's novel