The Iliad and Heike monogatari are each seen as seminal pieces of literature in Greek and Japanese culture respectively. Both works depict famous wars from which subsequent generations of warriors, poets, and other artists in each society drew their inspiration for their own modes of conduct and creation. While neither work is emphatically pro-war, both were used extensively by the warrior classes of both cultures to reinforce warrior culture and to inculcate proper battlefield behavior. In spite of this, however, both tales contain a strong undercurrent of anti-war sentiment which contrasts sharply with their traditionally seen roles of being tales about warriors and their glorious deeds. This thesis examines these works and details the presence of anti-war sentiment while also highlighting its emergence to greater prominence in later works found within the genres of Greek tragedy and nō theater. Ultimately, the Iliad and Heike monogatari act as foundational sources of anti-war sentiment for the later dramatic works, which poets of both cultures used to decry the woeful effects of war on both combatants and the innocent. By examining the presence of anti-war sentiment in two cultures that share surprising similarities but are widely separated by geography and chronology, we are presented with both a broader and deeper understanding of the effects of warfare on society and of the historical responses of citizen populations to events in war.