This article deals with a theological treatise that has been wrongly ascribed to the Imāmī scholar al-Sharīf al-Murtaḍā (d. 436/1044). The treatise discusses the question of human agency in relation to divine decree and determining, arguing for positions that, to a large extent, resemble Murtaḍā’s known views. Nevertheless, the treatise also betrays features incompatible with Murtaḍā’s theology as a whole, in addition to stylistic and bibliographical questions that make a good case against the work’s authenticity. This wrong ascription, however, has not been noted despite the repeated editions of the text in the Islamic world. As such, it misrepresented many of Murtaḍā’s views, sometimes undermining the main pillars of his theological system. The author of the treatise establishes his ethical concepts on the basis of scriptural dictates before proceeding to rational arguments, relies on non-multi-attested reports, defers to the authority of the Prophet’s companions and culls God’s names and attributes from the word of revelation. While going against Murtaḍā’s positions, these views – put together – are considerably closer to non-Imāmī doctrines, and could have easily been the work of a Muʿtazilī author.