We report the first record of the Diadem Snake, Spalerosophis diadema cliffordii (Schlegel, 1837) for Lebanon, based on an adult male found in the semi-desert area of the Beqaa Valley. This record increases the number of species of reptiles for Lebanon to 52, with the family Colubridae now comprising 17. The record also highlights the Beqaa Valley as a promising, but currently insufficiently investigated area for further herpetological research due to its biogeographic connection to the large semi-desert and desert areas of Syria.