The significance of the Battle of Agincourt as a turning point in the Hundred Years' War lies in its remarkable outcome despite overwhelming odds. Fought on October 25, 1415, English forces under King Henry V achieved a decisive victory against a numerically superior French army. This battle showcased the effectiveness of the English longbow and altered the course of the war in favor of England. The victory strengthened English morale, bolstered support for Henry's campaign, and contributed to the eventual rise of England in the ongoing conflict over French territories.