| Island's Name | Island group(s) | Country/Countries |
|---|
| Gabaret | Mississippi River,  Illinois |  United States |
| Gabriola | Gulf Islands,  British Columbia |  Canada |
| Gaga | Beira Litoral Islands |  Portugal |
| Gaivota | Beira Litoral Islands | Portugal |
| Gairsay | The North Isles,  Orkney Islands |  Scotland |
| Galiano | Gulf Islands, British Columbia | Canada |
| Galila | Lake Zway |  Ethiopia |
| Gall | Lough Erne |  Ireland |
| Gallinara | |  Italy |
| Galt | North Channel,  Ontario | Canada |
| Galveston |  Texas | United States |
| Gansy | Lake Winnipesaukee,  New Hampshire | United States |
| Gapøya | |  Norway |
| Garden | Lake Huron, Ontario | Canada |
| Garden | Lake Nipissing, Ontario | Canada |
| Garden | Saint Lawrence River, Ontario | Canada |
| Garden |  Western Australia |  Australia |
| Gardner |  Louisiana | United States |
| Garove | Vitu Islands |  Papua New Guinea |
| Garratt | West Lake Ontario | Canada |
| Gasket | West Lake Ontario | Canada |
| Gateshead |  Nunavut | Canada |
| Gaua | Banks Islands |  Vanuatu |
| Gavi | Pontine Islands | Italy |
| Gavdos | |  Greece |
| Geada | Algarve Islands | Portugal |
| Geike | Lake Nipigon, Ontario | Canada |
| Gelila Zakarias | Lake Tana | Ethiopia |
| Genovesa | Galápagos Islands |  Ecuador |
| Geomundo | |  South Korea |
| George |  Falkland Islands |  United Kingdom |
| George | Georgian Bay, Ontario | Canada |
| Georgetown | Ohio River,  Pennsylvania | United States |
| Georgina | Lake Simcoe, Ontario | Canada |
| Germ | Persian Gulf |  Iran |
| Geronisos | |  Cyprus |
| Gertrude | North Channel, Ontario | Canada |
| Gerumajima | Kerama Islands part of the Okinawa Islands part of the Ryukyu Islands |  Japan |
| Gęsia Kępa | Oder Lagoon islands |  Poland |
| Ghegheto | Lake Huron, Ontario | Canada |
| Giannutri |  Tuscan Archipelago | Italy |
| Giants Tomb | Georgian Bay, Ontario | Canada |
| Gibbs | South Shetland Islands | Claimed by:
Argentine Antarctica,  Argentina,
 Antártica Chilena Province of  Chile, and
 British Antarctic Territory of the United Kingdom |
| Gibraltar Island | Lake Erie,  Ohio | United States |
| Gidicho | Lake Abaya | Ethiopia |
| Gigha | Inner Hebrides | Scotland |
| Giglio | Tuscan Archipelago | Italy |
| Gil | British Columbia | Canada |
| Gilbert | Mississippi River,  Missouri | United States |
| Gilford | British Columbia | Canada |
| Gimsøya | Lofoten | Norway |
| Gioura | Sporades | Greece |
| Giudecca |  Venetian Lagoon | Italy |
| Giske | Møre og Romsdal | Norway |
| Gisløy | | Norway |
| Glimps Holm | Orkney Islands | Scotland |
| Glines | Lake Winnipesaukee, New Hampshire | United States |
| Gloup Holm |  Shetland Islands | Scotland |
| Glykiotissa | | Cyprus |
| Goat | Lough Erne | Ireland |
| Goat | Whitsunday Islands,  Queensland | Australia |
| Goat | Sydney Harbour | Australia |
| Goat | Auckland Region |  New Zealand |
| Goat | Otago Harbour | New Zealand |
| Goat | Niagara Falls  New York | United States |
| Goat |  Rhode Island | United States |
| Goat |  Maine | United States |
| Goat | North Channel, Ontario | Canada |
| Goat |  South Carolina | United States |
| Gödi-sziget | |  Hungary |
| Godøy | | Norway |
| Goeree-Overflakkee | part of the Dutch province South Holland |  Netherlands |
| Gokceada | Aegean Islands |  Turkey |
| Golem Grad | Lake Prespa |  North Macedonia |
| Goli otok | translates as "naked island" |  Croatia |
| La Gomera |  Canary Islands |  Spain |
| Goodin | Mississippi River, Minnesota | United States |
| Goose Island | Great Salt Lake,  Utah | United States |
| Goose | Lake Nipissing, Ontario | Canada |
| Goose | British Columbia | Canada |
| Goose | San Juan Islands,  Washington | United States |
| Gooseberry | North Channel, Ontario | Canada |
| Gorée | Dakar |  Senegal |
| Gorgona | |  Colombia |
| Gorgona | Tuscan Archipelago | Italy |
| Gossa | | Norway |
| Gotland | |  Sweden |
| Gotska Sandön | | Sweden |
| Gough |  Tristan da Cunha | British overseas territory of Saint Helena, Ascension and Tristan da Cunha |
| Governor | Thimble Islands,  Connecticut | United States |
| Governor | Georgian Bay, Ontario | Canada |
| Governors | Lake Winnipesaukee, New Hampshire | United States |
| Gower | Cumberland River,  Tennessee | United States |
| Gozo | Għawdex, Maltese islands |  Malta |
| Graciosa |  Azores | Portugal |
| Graciosa | Canary Islands | Spain |
| Graemsay | Orkney Islands | Scotland |
| Graham | Queen Elizabeth Islands, Nunavut | Canada |
| Graham | Haida Gwaii, British Columbia | Canada |
| Gramatal Island | Beira Litoral Islands | Portugal |
| Gran Canaria | Canary Islands | Spain |
| Granary | Islands of Gdańsk | Poland |
| Grand Cayman |  Cayman Islands | United Kingdom |
| Grand | Jason Islands of the Falkland Islands | United Kingdom |
| Grand | Balsam Lake, Ontario | Canada |
| Grand | Louisiana | United States |
| Grand | Niagara River, New York | United States |
| Grand | Lake Champlain,  Vermont | United States |
| Grand Manan |  New Brunswick | Canada |
| Grand Terre | Louisiana | United States |
| Grande Comore | Comoros |  Comoros |
| Grande-Terre |  Guadeloupe, Lesser Antilles |  France |
| Grape | Lake Simcoe, Ontario | Canada |
| Gräsö | | Sweden |
| Gravelly | Lough Erne | Ireland |
| Gravine | Mobile Bay,  Alabama | United States |
| Gray | Georgian Bay, Ontario | Canada |
| Great Blasket | Blasket Islands | Ireland |
| Great Britain | | United Kingdom |
| Great | Falkland Islands | United Kingdom |
| Great | Cork Harbour | Ireland |
| Great |  Massachusetts | United States |
| Great Exuma | Bahama Islands |  Bahamas |
| Great La Cloche | North Channel, Ontario | Canada |
| Great Manitou | Lake Nipissing, Ontario | Canada |
| Great Nicobar | Nicobar Islands |  India |
| Greater Mount Changtu | Zhoushan Archipelago |  China |
| Greater Mount Yang | Zhoushan Archipelago | China |
| Greater Tunbs | Persian Gulf | Iran |
| Green | Queensland | Australia |
| Green |  New South Wales | Australia |
| Green |  Jersey, Channel Islands | Crown dependency |
| Green | Isles of Scilly | United Kingdom |
| Green | Poole Harbour | United Kingdom |
| Green | Rideau River, Ontario | Canada |
| Green | Severn Sound, Ontario | Canada |
| Greene | Ottawa River, Ontario | Canada |
| Green |  Hong Kong | China |
| Green | Taitung County |  Republic of China |
| Green | Red Sea |  Egypt |
| Greene | Lake Huron, Ontario | Canada |
| Greene | Lake Ontario, Ontario | Canada |
| Greenisland | Northern Ireland | United Kingdom |
Greenland  | |  Denmark |
| Greenspond |  Newfoundland and Labrador | Canada |
| Greenwich | South Shetland Islands | Claimed by:
Argentine Antarctica, Argentina,
Antártica Chilena Province of Chile, and
British Antarctic Territory of the United Kingdom |
| Grenadier | Thousand Islands New York | United States |
| Grenadier | Saint Lawrence River Ontario | Canada |
| Greifswalder Oie | |  Germany |
| Grgur | | Croatia |
| Gribbell | British Columbia | Canada |
| Griffith | Queen Elizabeth Islands, Nunavut | Canada |
| Griffith | Windmill Islands | Antarctica |
| Griffith | Georgian Bay, Ontario | Canada |
| Grimes | Mississippi River, Illinois | United States |
| Grímsey | |  Iceland |
| Grindstone | Thousand Islands (Saint Lawrence River), New York | United States |
| Grindstone | Big Rideau Lake, Ontario | Canada |
| Grip | | Norway |
| Gris Bourbe | Louisiana | United States |
| Grisvågøy | | Norway |
| Gröde-Appelland | North Frisian Islands | Germany |
| Groix | Morbihan,  Bretagne | France |
| Grøtøy | | Norway |
| Grunay | Out Skerries, Shetland Islands | Scotland |
| Gruney | Shetland Islands | Scotland |
| Grytøy | Vesterålen | Norway |
| Guam | | United States |
| Guana Key | Island Territory of Sint Maarten,  Netherlands Antilles | Kingdom of the Netherlands |
| Guemes | San Juan Islands, Washington | United States |
| Guernsey |  Guernsey, Channel Islands | Crown dependency |
| Gull | Lake Nipissing, Ontario | Canada |
| Gull | Lake Ontario, Ontario | Canada |
| Gull | Lake Mead,  Nevada | United States |
| Gunnison | Great Salt Lake, Utah | United States |
| Gurskøy | | Norway |
| Gyali | Dodecanese | Greece |
| Gyaros | Cyclades | Greece |
