An updated checklist of treehoppers (Hemiptera: Membracidae) of Panama is provided with known province distribution data. The world catalogue of Membracoidea, through April, 1997, lists 68 genera, 162 species, and 1 subspecies from Panama (McKamey, 1998). Flynn (2012) listed all known species from Panama, documenting range extensions for 29 genera, 107 species, and 1 subspecies previously unknown from Panama, bringing the treehopper fauna from Panama to 97 genera, 269 species, and 2 subspecies. Inspection of 768 additional specimens since 2012 (new total of 3,595 specimens for the study), in addition to published literature, has added 2 new genera and 40 new species bringing the treehopper fauna to 100 genera (increase of 3 genera), 313 species (increase of 44 species) from 2012, and 2 subspecies. Many new provincial sites were added to each species with an updated provincial map showing numbers of species in each province. Updated species counts per Province (with increase): Bocas del Toro 65 (+10), Chiriqui 162 (+11), Veraguas 26 (+3), San Blas 8 (+1), Herrera 9 (+1), Darien 72 (+13), Los Santos 4 (+1), Cocle 43 (+9), Colon 187 (+79), and Panama 150 (+32). Tables listing published checklists and keys for Nearctic and Neotropical treehoppers are presented.