| Indiana Repertory TheatreEIN 35-1186290 | Arts, Culture, Humanities | IN | $7,233,067Mid-sized | 88.31 |
| Indianapolis Urban LeagueEIN 35-6060655 | Human and Civil Rights | IN | $2,226,625Small | 84.04 |
| Indianapolis ZooEIN 35-1074747 | Animals | IN | $32,985,416Large | 88.11 |
| InFaith Community FoundationEIN 41-1802412 | Community Development | MN | $27,770,587Large | 89.55 |
| Inner City Christian FederationEIN 38-1903026 | Community Development | MI | $3,981,359Mid-sized | 80.42 |
| Inner City Health CenterEIN 74-2426085 | Health | CO | $4,248,776Mid-sized | 85.49 |
| Inner-City Scholarship FundEIN 51-0453629 | Education | NY | $17,315,161Large | 88.90 |
| Insight for LivingEIN 95-3392299 | Religion | TX | $19,580,163Large | 82.54 |
| Inspiration CorporationEIN 36-3673980 | Human Services | IL | $3,630,945Mid-sized | 84.09 |
| Institute for Agriculture and Trade PolicyEIN 36-3501938 | Research and Public Policy | MN | $1,790,307Small | 83.92 |
| Institute for America's FutureEIN 52-1971942 | Research and Public Policy | DC | $2,915,846Small | 83.56 |
| Institute for Educational AdvancementEIN 95-4695698 | Education | CA | $2,150,889Small | 89.48 |
| Institute for Energy ResearchEIN 76-0149778 | Research and Public Policy | DC | $1,666,571Small | 89.48 |
| Institute for Global EngagementEIN 23-3042456 | International | VA | $1,479,806Small | 85.85 |
| Institute for Humane StudiesEIN 94-1623852 | Education | VA | $18,238,447Large | 83.65 |
| Institute for Middle East UnderstandingEIN 20-2389388 | International | CA | $1,491,358Small | 85.79 |
| Institute for Quality EducationEIN 35-1836687 | Education | IN | $9,090,608Mid-sized | 86.44 |
| Institute for the Study of WarEIN 26-0273675 | Research and Public Policy | DC | $1,843,667Small | 81.77 |
| Institute for Transportation and Development PolicyEIN 52-1399520 | Environment | NY | $7,664,135Mid-sized | 87.62 |
| Institute for Women's Policy ResearchEIN 52-1549572 | Research and Public Policy | DC | $3,176,103Small | 86.79 |
| Institute of International EducationEIN 13-1624046 | International | NY | $358,197,642Large | 83.33 |
| Institute of Noetic SciencesEIN 23-7236986 | Research and Public Policy | CA | $5,024,895Mid-sized | 87.56 |
| Inter-Faith Food ShuttleEIN 56-1753180 | Human Services | NC | $13,594,451Large | 82.98 |
| InterActEIN 58-1320613 | Human Services | NC | $3,155,277Small | 89.26 |
| InterAct MinistriesEIN 92-6004561 | Religion | OR | $2,315,997Small | 84.18 |
| Interface MinistriesEIN 58-1970866 | Religion | GA | $1,206,568Small | 86.94 |
| Interfaith Assistance MinistryEIN 58-1556963 | Human Services | NC | $1,014,698Small | 87.89 |
| Interfaith Caring MinistriesEIN 76-0143694 | Human Services | TX | $1,230,577Small | 83.85 |
| Interfaith Community Housing of DelawareEIN 51-0298556 | Community Development | DE | $1,820,586Small | 86.24 |
| Interfaith Dental ClinicEIN 62-1567615 | Health | TN | $3,178,785Small | 83.70 |
| Interfaith Education FundEIN 74-2548241 | Education | TX | $1,714,577Small | 81.01 |
| InterFaith Health ClinicEIN 58-1947641 | Health | TN | $2,717,785Small | 88.10 |
| Interfaith Power & LightEIN 94-3335236 | Environment | CA | $1,481,890Small | 82.03 |
| Interfaith Social ServicesEIN 04-2104853 | Human Services | MA | $1,687,636Small | 89.02 |
| Interfaith WorksEIN 52-1072684 | Human Services | MD | $12,337,425Mid-sized | 84.98 |
| Interfaith Youth CoreEIN 30-0212534 | Religion | IL | $6,458,253Mid-sized | 89.33 |
| InterfaithFamilyEIN 04-3577816 | Religion | MA | $2,977,372Small | 83.71 |
| Interlochen Center for the ArtsEIN 38-1689022 | Education | MI | $55,453,968Large | 86.94 |
| International Campaign for TibetEIN 52-1570071 | International | DC | $3,169,181Small | 87.16 |
| International Center for Research on WomenEIN 52-1081455 | International | DC | $12,380,625Mid-sized | 83.72 |
| International Center of PhotographyEIN 23-7412428 | Arts, Culture, Humanities | NY | $17,276,229Large | 81.79 |
| International Christian MinistriesEIN 62-1465626 | Religion | CA | $939,719Small | 80.19 |
| International Eye FoundationEIN 52-0742301 | International | MD | $4,553,179Mid-sized | 81.58 |
| International Fellowship of Christians and JewsEIN 36-3256096 | International | IL | $134,425,717Large | 85.68 |
| International Festival of Arts & IdeasEIN 06-1444222 | Arts, Culture, Humanities | CT | $2,299,189Small | 82.87 |
| International Friendships, Inc.EIN 31-0971249 | Religion | OH | $1,909,000Small | 87.24 |
| International Fund for Animal WelfareEIN 31-1594197 | Animals | MA | $23,001,672Large | 80.88 |
| International HouseEIN 13-1624048 | International | NY | $16,690,286Large | 88.41 |
| International Justice MissionEIN 54-1722887 | International | DC | $64,086,117Large | 87.44 |
| International Medical CorpsEIN 95-3949646 | International | CA | $138,130,256Large | 84.22 |
| International Mountain Bicycling AssociationEIN 47-1254119 | Human Services | CO | $3,932,971Mid-sized | 80.31 |
| International NeedsEIN 91-1080666 | Religion | MI | $2,927,719Small | 88.95 |
| International OCD FoundationEIN 22-2894564 | Health | MA | $2,018,242Small | 88.32 |
| International Orthodox Christian CharitiesEIN 25-1679348 | International | MD | $40,613,412Large | 85.85 |
| International Psoriasis CouncilEIN 20-1566278 | Health | MO | $1,324,090Small | 82.17 |
| International RiversEIN 94-3158295 | Environment | CA | $2,122,078Small | 82.97 |
| International Senior Lawyers CorporationEIN 52-2241212 | Human and Civil Rights | NY | $1,291,304Small | 82.82 |
| International Society for Infectious DiseasesEIN 22-2473000 | Health | MA | $2,177,843Small | 87.68 |
| International Tennis Hall of FameEIN 13-6144356 | Arts, Culture, Humanities | RI | $10,386,956Mid-sized | 85.30 |
| InterServe USAEIN 23-1644377 | Religion | PA | $6,078,115Mid-sized | 85.85 |