| G. Pascoli Observatory | Castelvecchio Pascoli | — |
 G.V. Schiaparelli Observatory | Varese | 1.226 m |
| Galhassin Robotic Telescope observatory | Isnello | — |
| Geminiano Montanari Observatory | Cavezzo | 18 m |
| Genoa observatory | Génova | — |
| GERmanium Detector Array | — | — |
| GiaGa Observatory | Pogliano Milanese | — |
| Giordano Bruno Observatory | Brallo di Pregola | — |
| Giuseppe Conzo's Observatory | — | — |
| Giuseppe Piazzi observatory | Ponte in Valtellina | — |
| Gorgonzola Observatory | Gorgonzola | — |
| Gottolengo observatory | Gottolengo | — |
| Granda observatory | Aviatico | — |
| Grange Observatory | Bussoleno | — |
| Gravina in Puglia observatory | Gravina in Puglia | — |
| Gruppo Astrofili Catanesi | Catania | — |
| Guido Ruggieri Observatory | Padua | — |
| Gwen Observatory | San Francesco al Campo | — |
| Helmut Ullrich Astronomical Observatory | Cortina d’Ampezzo | — |
| HOB Observatory | Capraia | — |
| Hypatia Observatory | Rímini | — |
| Iota Scorpii Observatory | La Spezia | — |
| ISON-Castelgrande Observatory | Castelgrande | — |
| Istituto Nazionale di Geofisica e Vulcanologica - Sezione di Catania | Catania | — |
| Jonathan B. Postel Observatory | Promiod | — |
| Keyhole Observatory | Mantua | — |
| L'Aquila Magnetic Observatory | — | 682 m |
| La Giustiniana observatory | Roma | — |
| Large Volume Detector | — | — |
| Libbiano astronomical observatory | Libbiano | — |
| Livergnano observatory | Pianoro | — |
| Livorno observatory | Livorno | — |
| Loiano observatory | Loiano | — |
| Lomazzo Observatory | Bissago | — |
| Lucca observatory | Lucca | — |
 Lumezzane observatory | Lumezzane | — |
| M57 Observatory | Saltrio | — |
| Magroforte observatory | Magroforte Inferiore | — |
| Malina River observatory | Ravosa-Magredis | — |
| Mandi observatory | Údine | — |
| Marana observatory | Crespadoro | — |
| Margherita Hack observatory | Florencia | — |
| Marina di Cerveteri observatory | Marina di Cerveteri | — |
| Maritime Alps Observatory | Cuneo | — |
| Martesana Observatory | Cassina de' Pecchi | — |
| Matera Laser Ranging observatory | Matera | — |
| Max Valier Sat | — | — |
| Merate astronomical observatory | Merate | — |