Siblings are our longest lasting relationships. Narratives of the Great War abound with the war stories of brothers and sisters. Their emotional experiences span the novelty of departing for war or taking up war work, the turmoil of facing combat, the effort to provide ongoing support for family members, the ever-present anxiety for soldier-brothers, the depth of sibling grief and the multifarious ways surviving siblings sought to preserve the memory of their fallen brothers. This social and cultural history places siblinghood at the heart of our understanding of the war generation and how they balanced conflicting obligations to the nation, the military and their families. Drawing on a range of material, Brothers in the Great War, reveals how sibling bonds sustained fighting men and presents a novel insight into twentieth-century familial life.