The "Letter to Flora" is a Gnostic text written by Ptolemy, a Valentinian teacher, to a woman named Flora.
Prior to the discovery of the Nag Hammadi Library, the Letter was one of the few authentic Gnostic works available to scholars. The letter was included in full in Epiphanius's Panarion, an unsympathetic text which condemns its theology as heretical. Ptolemy's beliefs are also known from the writings of Irenaeus.