Scholars have disagreed on whether Cicero’s De Amicitia is a philosophically serious or even coherent work. Such criticisms, I believe, can be met by an examination of the successive accounts of friendship that the character of Gaius Laelius provides in the dialogue. I argue that the dialogue offers three such accounts of friendship which taken together provide a comprehensive and coherent account of friendship. Further, I defend Cicero’s account against criticisms that Aulus Gellius had raised in the 2nd century CE (criticisms that have been repeated to the modern day). The problem of defining friendship is a thread that brings unity to the entire dialogue and shows Cicero philosophizing about both the origins of friendship and its dissolution, especially when the bonds of friendship are in tension with obligations to the political community.