Encyclopedias, Almanacs, Transcripts, and Maps
- Guillaume Benjamin Amand Duchenne
- Guillaume Cassegrain
- Guillaume de Carpentras (ca. 15th century)
- Guillaume de Paris (ca. 1180-1249)
- Guillaume-François-Antoine de l'Hospital
- Guinea Pigs and Cavies
- Guinea Pigs and Cavies
- Guineafowl
- Guineafowl: Numididae
- Guinefort, St
- Guion S. Bluford
- Guirdham, Arthur (1905-?)
- Guiseppe Peano
- Guiseppe Piazzi
- Guldenstubbe, Baron L(udwig) von(1820-1873)
- Gulls, Terns, and Relatives: Laridae
- Gulls, Terns, Plovers, and Other Shorebirds: Charadriiformes
- Gundicar
- Gundis: Ctenodactylidae
- Gunnbjorn Ulfsson