On Fate (Latin: De Fato) is a partly extant work by Cicero, written in 44 BC, in which he discusses fate and freedom of the will with his friend Aulus Hirtius. Although ostensibly a dialogue, the surviving portions contain long passages of exposition by Cicero. The work appears to be closely connected to On the Nature of the Gods and On Divination.
Free online texts
Internet Archive: The treatises of M.T. Cicero: On the nature of the gods; On divination; On fate; On the republic; On the laws; and On standing for the consulship. Literally translated chiefly by the editor, C.D. Yonge (1878). Multiple formats.
Internet Archive: De natura deorum, De divinatione, De fato, edited by Reinholdus Klotz (1879). Latin text, multiple formats.
Latin Library: De Fato. Latin text, HTML format.
Perseus: De Fato. Latin text, edited by C.F.W. Muller (Teubner, 1915). HTML and XML formats.
Wikisource: De Fato. Latin text, multiple formats.
History of Philosophy without any gaps: Rhetorical Questions: Cicero - podcast by philosopher Peter Adamson.
History of Philosophy without any gaps: Raphael Woolf on Cicero - podcast by philosopher Peter Adamson.
Internet Encyclopedia of Philosophy: Cicero.
The Great Conversation: Further reading at Tom's Learning Notes
Cicero: On the Nature of the Gods.
Cicero: On Divination.
Latin resources: Learn to read Latin texts in the original.