The Acts of Ptolemy and Lucius is an early Christian text from the Roman era, written in the 2nd century CE. It is not a standalone book but a short martyrdom story embedded within the Second Apology of the Christian philosopher Justin Martyr, who wrote around 155–160 CE. The text presents itself as a record of a trial in Rome under Emperor Marcus Aurelius, where Ptolemy, a Christian teacher, is condemned to death. A bystander named Lucius protests the verdict and is also executed.

The author of this martyr act is anonymous, and its historical accuracy is debated by scholars. It is considered a literary example of a genre where early Christians documented the witness and deaths of believers. According to modern scholars, Justin Martyr included this narrative to provide a concrete example of the legal injustices faced by Christians, using it to argue for the reasonableness of their faith.

This brief account is significant as one of the earliest examples of Christian martyr literature. It illustrates the growing tensions between Roman authority and Christian communities in the 2nd century. Academics view it as an important source for understanding how early Christians shaped their identity and defended their beliefs through stories of persecution, helping to establish a literary tradition that would become central to Christian history.