Greenland
noun: Greenlander(s)
adjective: Greenlandic
Grenada
noun: Grenadian(s)
adjective: Grenadian
Guadeloupe
noun: Guadeloupian(s)
adjective: Guadeloupe
Guam
noun: Guamanian(s) (US citizens)
adjective: Guamanian
Guatemala
noun: Guatemalan(s)
adjective: Guatemalan
Guernsey
noun: Channel Islander(s)
adjective: Channel Islander
Guinea
noun: Guinean(s)
adjective: Guinean
Guinea-Bissau
noun: Guinean(s)
adjective: Guinean
Guyana
noun: Guyanese (singular and plural)
adjective: Guyanese
Haiti
noun: Haitian(s)
adjective: Haitian