| IFA | Industrieverband Fahrzeugbau |
| Ifat | Ifat |
| Ife | Ife |
| Ifejon | Ipheion |
| Iffeldorf | Iffeldorf |
| Iffezheim | Iffezheim |
| Ifigenia | Iphigeneia |
| Ifigenia w Aulidzie | Iphigeneia at Aulis |
| Ifigenia w Taurydzie | Iphigeneia in Tauris |
| Ifikles | Iphicles |
| Ifitos | Iphitos |
| IFK Göteborg | IFK Göteborg |
| IFK Malmö | IFK Malmö |
| IFLA | International Federation of Library Associations and Institutions |
| IFLRY | International Federation of Liberal Youth |
| IFMIF | International Fusion Materials Irradiation Facility |
| IFolder | IFolder |
| IFOR | IFOR |
| IFR | Instrument flight rules |
| Ifrit | Ifrit |
| IFS | Iterated function system |
| iftar | iftar |
| IG Farben | IG Farben |
| Iga | IGA |
| Igalo | Igalo |
| Igarka | Igarka |
| IGBT | Insulated-gate bipolar transistor |
| IGCC | Combined cycle |
| Igensdorf | Igensdorf |
| Igerna | Igraine |
| Igersheim | Igersheim |
| IGES | IGES |
| Iggensbach | Iggensbach |
| Iggingen | Iggingen |
| Iggy Pop | Iggy Pop |
| Igieůka | Needle |
| Igis | Igis |
| Iglaste | Pinophyta |
| iglasty | coniferous |
| Iglesias | Iglesias |
| iglica | steeple |
| Iglica pospolita | Erodium cicutarium |
| iglicznia | pipefish |
| Igliczniokształtne | Syngnathiformes |
| Igliczniowate | Syngnathidae |
| Igling | Igling |
| igloo | igloo |
| Ignacio Eizaguirre | Ignacio Eizaguirre |
| Ignacy | Ignatius |
| Ignacy Afram I Barsoum | Ignatius Afram I Barsoum |
| Ignacy Antiocheński | Ignatius of Antioch |
| Ignacy Domeyko | Ignacy Domeyko |
| Ignacy Eliasz III | Ignatius Elias III |
| Ignacy Friedman | Ignaz Friedman |
| Ignacy Hryniewiecki | Ignacy Hryniewiecki |
| Ignacy I Daoud | Ignace I Daoud |
| Ignacy Jakub III | Ignatius Ya`qub III |
| Ignacy Jan Paderewski | Ignacy Jan Paderewski |
| Ignacy Krasicki | Ignacy Krasicki |
| Ignacy Loyola | Ignatius of Loyola |
| Ignacy Mościcki | Ignacy Mościcki |
| Ignacy Wyssogota Zakrzewski | Ignacy Wyssogota Zakrzewski |
| Ignacy Zakka I Iwas | Ignatius Zakka I Iwas |
| Ignacy Łukasiewicz | Ignacy Łukasiewicz |
| Ignalina | Ignalina |
