Conduct in human relationships, in amicitia (‘friendship’), is a prevalent theme in Horace's works, and was of considerable interest to ancient philosophers. The extent to which such aspects of human behaviour should be regarded as philosophical is a question that has been discussed both in relation to ancient philosophical texts and to Horace. My concern here, however, is not primarily to argue for their philosophical nature but to illuminate certain influences in the Satires and Epistles that draw on philosophical texts pertaining to conduct and amicitia, and in particular those of Horace's near contemporary, Philodemus.