3 occurrences across the corpus

King James Version

Luke 1:3

It seemed good to me also, having had perfect understanding of all things from the very first, to write unto thee in order, most excellent Theophilus,

Acts 1:1

The former treatise have I made, O Theophilus, of all that Jesus began both to do and teach,

OT Pseudepigrapha

The Letter of Aristeas 2:44

Of the ninth tribe, Theophilus, Abraham, Arsamos, Jason, Endemias, Daniel.