- ibera
- iliac-carapacial connection
- imbricata
- impressa
- inbreeding
- incisa
- incisive foramen
- indi
- indica
- indopeninsularis
- Indotestudo
- infraclass
- inframarginal scutes
- infraorder
- inguinal buttresses
- inguinal notch
- insculpta
- insectivorous
- integrum
- integument
- interabdominal
- interanal scute
- interbreed
- interclavicle
- intergular scute
- intergularis
- interpterygoid vacuity
- interspecific
- interstitial cells
- intestine
- intrapulmonary
- intrauterine phase
- introgression
- invertebrate
- irwini
- Isabela Island
- ischiadic symphyses
- ischium
- isthmus
- IUCN
- IUCN Categories of Threat
- IUCN Red List of Threatened Animals
- iversoni