4 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,

NT Apocrypha/Pseudepigrapha

The Third Epistle to the Corinthians 1:3

Stephanus and the elders that are with him, even Daphnus and Eubulus and Theophilus and Zenon, unto Paul their brother eternal greeting in the Lord.

OT Pseudepigrapha

The Letter of Aristeas 2:44

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