Foundations starting with O
160 private foundations with profiled giving history. Figures from IRS 990-PF filings. Search every letter at once.
Typical grant is the median of grants reported in the filing data. Application details come from the latest filing and can be out of date, so confirm them with the foundation.
1–100 of 160 foundations in this list.
| Foundation | Typical grant | Total giving | Grants reported |
|---|---|---|---|
| O'Donnell Foundation IRS filing 2025 · Most giving: TX, VA | $1M | $218.8M | 43 |
| Open Society Institute IRS filing 2024 · Most giving: NY, DC, CA | $15K | $146.9M | 559 |
| Otto Bremer Trust IRS filing 2025 · Most giving: MN, WI, ND | $55K | $125.8M | 1,063 |
| One8 Foundation IRS filing 2024 · Most giving: MA, NY, CA | $50K | $48.8M | 188 |
| The O Wayne Rollins Foundation C/O Rfa Management Co LLC IRS filing 2024 · Most giving: GA, KY, FL | $2K | $39.5M | 29 |
| Omidyar Network Fund Inc IRS filing 2024 · Most giving: DC, NY, CA | $100K | $38.1M | 242 |
| Oberndorf Family Foundation IRS filing 2025 · Most giving: CA, TX, OH | $25K | $36M | 112 |
| Orland Bethel Family Foundation IRS filing 2025 · Most giving: PA, NY, MA | $7.5K | $27.8M | 10 |
| Osteopathic Heritage Foundation IRS filing 2025 · Most giving: OH, MD, IL | $47.5K | $24.5M | 129 |
| The Oprah Winfrey Charitable Foundation IRS filing 2024 · Most giving: CA, IL, MD | $150K | $23.4M | 25 |
| Open Doors International Inc IRS filing 2024 · Most giving: JOHANNESBURG, HARDERWIJK, QUEZON CITY | $611.7K | $22.6M | 9 |
| Oneroot Foundation IRS filing 2025 · Most giving: CA, CO, NY | $25K | $15.1M | 104 |
| The Otis Booth Foundation IRS filing 2023 · Most giving: CA, NY, ID | $25K | $14.4M | 140 |
| The Oak Foundation USA C/O Kemnay Advisory Services Inc IRS filing 2025 · Most giving: HI, MA, NY | $400.8K | $14.3M | 16 |
| The Orokawa Foundation Inc C/O Martin J Eby IRS filing 2024 · Most giving: MD, NY, IL | $50K | $11.1M | 115 |
| Once Upon A Time Foundation IRS filing 2024 · Most giving: TX, NC, DC | $350 | $10.7M | 1,039 |
| Onesight Essilorluxottica Foundation Fund IRS filing 2024 · Most giving: GASABO, KIGALI CI, CHENNAI, JOHANNESBURG | $27.7K | $10.3M | 79 |
| Offutt Family Foundation IRS filing 2024 · Most giving: MN, ND, NY | $5K | $9.6M | 114 |
| October Mountain Foundation Inc IRS filing 2025 · Most giving: NY, MI, MA | $30K | $9.4M | 141 |
| O'Neill Family Charitable Trust IRS filing 2024 · Most giving: NY, VA, MA | $20K | $8.5M | 149 |
| The Overbrook Foundation IRS filing 2024 · Most giving: NY, DC, CA | $47.5K | $8.3M | 160 |
| The Oak Hill Fund IRS filing 2025 · Most giving: VA, CO, FL | $25K | $8M | 206 |
| Otto Schoitz Foundation IRS filing 2024 · Most giving: IA, MA | $25K | $7.2M | 108 |
| Oakwood Foundation Charitable Trust IRS filing 2024 · Most giving: VA, NC, DC | $10K | $6.9M | 46 |
| Orange Crimson Foundation IRS filing 2024 · Most giving: NY, VA, GA | $1M | $6.5M | 5 |
| The Oscar Rennebohm Foundation Inc IRS filing 2025 · Most giving: WI | $75K | $6.3M | 73 |
| Oberkotter Foundation IRS filing 2024 · Most giving: DC, CT, IL | $154.4K | $6.3M | 17 |
| Ono Pharma Foundation IRS filing 2025 · Most giving: CA, MA, MI | $258.8K | $6.2M | 24 |
| The Osprey Foundation Inc IRS filing 2024 · Most giving: MD, DC, NY | $150K | $6.1M | 27 |
| Orscheln Industries Foundation Inc IRS filing 2024 · Most giving: MO, KS, VA | $1K | $6M | 552 |
| Oechsle Family Foundation Inc IRS filing 2025 · Most giving: CT, MA, IL | $50K | $6M | 92 |
| Oscar J Tolmas Charitable Trust IRS filing 2025 · Most giving: LA, TX, MS | $25K | $5.9M | 142 |
| Opus Foundation IRS filing 2024 · Most giving: MN, CO, MO | $10K | $5.5M | 164 |
| The Oliver Family Foundation C/O Richard D Oliver IRS filing 2025 · Most giving: OH, MI, ME | $11.3K | $5.2M | 120 |
| Obici Healthcare Foundation Inc IRS filing 2024 · Most giving: VA, NC | $4K | $5.2M | 118 |
| The Organix Foundation IRS filing 2025 · Most giving: Montreal, Quebec, Ottawa | $9.7K | $5.2M | 12 |
| Odell Rs & Hp Fund Tua-Main IRS filing 2025 · Most giving: CA, NJ, GA | $30K | $5.1M | 118 |
| O L Halsell Foundation IRS filing 2025 · Most giving: CA | $15K | $5M | 211 |
| The Owens Family Foundation IRS filing 2025 · Most giving: VA, MA | $100K | $4.6M | 17 |
| Olson Family Foundation Inc IRS filing 2025 · Most giving: OK, DC, NY | $25K | $4.4M | 128 |
| The Otho Sa Sprague Memorial Institute IRS filing 2025 · Most giving: IL, WA | $100K | $4.4M | 35 |
| Onion Foundation IRS filing 2024 · Most giving: ME, MA, VT | $15K | $4.4M | 245 |
| Oge Energy Corp Foundation Inc IRS filing 2024 · Most giving: OK, AZ, AR | $10K | $4.3M | 86 |
| The O'Connor & Hewitt Foundation IRS filing 2025 · Most giving: TX, MD | $10K | $4.1M | 155 |
| The Ohnell Family Foundation IRS filing 2025 · Most giving: NY, PA, CT | $10K | $4.1M | 82 |
| Oneok Foundation Inc IRS filing 2024 · Most giving: OK, ND, TX | $4.9K | $3.7M | 204 |
| Oppenstein Brothers Foundation IRS filing 2025 · Most giving: MO, KS | $15K | $3.6M | 236 |
| Oates Family Foundation IRS filing 2025 · Most giving: CA, MN, SC | $6.3K | $3.6M | 64 |
| Osullivan Foundation Trust Dtd 122299 IRS filing 2024 · Most giving: CA, NY, VA | $40K | $3.6M | 13 |
| The Oxford League Inc IRS filing 2025 · Most giving: NY, PA, MA | $50K | $3.6M | 25 |
| The O'Neil Family Foundation Inc IRS filing 2024 · Most giving: MD, WA, NY | $12K | $3.6M | 118 |
| Ousri Foundation for Goodwill IRS filing 2025 · Most giving: DC, RI, MN | $3.8K | $3.6M | 10 |
| Ormjmp Foundation IRS filing 2024 · Most giving: FL, DC, CA | $125K | $3.3M | 19 |
| Osilas Foundation IRS filing 2025 · Most giving: MN, VA, NY | $10K | $3.3M | 75 |
| Oakhill Foundation IRS filing 2025 · Most giving: OH | $194K | $3.3M | 8 |
| Old Ladies Home Association IRS filing 2024 · Most giving: MS | $63.5K | $3.2M | 15 |
| Oleson Foundation IRS filing 2025 · Most giving: MI, RI, WV | $11K | $3.2M | 159 |
| Ottumwa Regional Legacy Foundation Inc IRS filing 2024 · Most giving: IA, AR, TX | $1.1K | $3.1M | 216 |
| Oceanfirst Foundation IRS filing 2025 · Most giving: NJ, PA, NY | $1.1K | $3.1M | 1,087 |
| The Orchard Foundation C/O Heidi Lehner Corient Private Wealth IRS filing 2025 · Most giving: MA, NH, NY | $5K | $3.1M | 168 |
| The Onda Foundation Inc IRS filing 2025 · Most giving: VT, NY, PA | $20.3K | $3M | 98 |
| Oarsmen Foundation IRS filing 2024 · Most giving: CA, MA, CO | $20K | $2.9M | 77 |
| Odyssey Group Foundation IRS filing 2024 · Most giving: CT, NY, WA | $75K | $2.8M | 16 |
| Oscar T and Olivann Hokold Foundation IRS filing 2024 · Most giving: WA | $50K | $2.8M | 31 |
| Oak Ridge Foundation IRS filing 2024 · Most giving: TN | $1K | $2.8M | 14 |
| The Once Here Foundation IRS filing 2024 · Most giving: MA, OH, CO | $137.5K | $2.8M | 14 |
| Outrageous Foundation Inc C/O Robert McGrath IRS filing 2024 · Most giving: CA, NM, KS | $30K | $2.7M | 81 |
| Olive B Cole Foundation Inc IRS filing 2025 · Most giving: IN, MI | $13K | $2.7M | 111 |
| O'Loughlin Family Foundation IRS filing 2025 · Most giving: MO | $15K | $2.7M | 7 |
| The Owsley Brown III Philanthropic Found IRS filing 2023 · Most giving: KY, CA, IA | $10K | $2.7M | 95 |
| On Semiconductor Foundation IRS filing 2024 · Most giving: DE, TAVISTOCK, DEVON | $12.5K | $2.6M | 6 |
| O Temple Sloan Jr Foundation IRS filing 2023 · Most giving: NC, MT, TX | $6.5K | $2.6M | 199 |
| One Gas Foundation Inc IRS filing 2024 · Most giving: OK, TX, KS | $2.4K | $2.6M | 212 |
| OReilly Automotive Foundation Inc IRS filing 2025 · Most giving: DC, MO, IL | $20K | $2.5M | 87 |
| Opportunity Foundation IRS filing 2024 · Most giving: PA, CA, NY | $15K | $2.4M | 156 |
| Oppenheimer&Haas Xxxxx1004 IRS filing 2025 · Most giving: NY, MA | $70K | $2.4M | 27 |
| Oceanic Heritage Foundation C/O Morgan Stanley IRS filing 2025 · Most giving: NY, CT, MD | $15K | $2.4M | 78 |
| Ohel Harav Yehoshua Boruch Foundation Inc IRS filing 2024 · Most giving: NY, NJ | $50K | $2.4M | 9 |
| Open Horizon IRS filing 2024 · Most giving: VA, DC, NY | $18.4K | $2.4M | 83 |
| Otis & Bettina Chandler Foundation IRS filing 2025 · Most giving: CA, NY, DC | $37.5K | $2.4M | 26 |
| Oshkosh Corporation Foundation Inc IRS filing 2025 · Most giving: WI, FL, MN | $6.5K | $2.4M | 133 |
| Oclo Inc IRS filing 2024 · Most giving: NY, OH, FL | $85K | $2.3M | 13 |
| Otha H Grimes Foundation IRS filing 2025 · Most giving: OK, AR | $287.5K | $2.3M | 8 |
| One Life Foundation Inc IRS filing 2023 · Most giving: OH, MA | $218.8K | $2.3M | 5 |
| One Hive Foundation IRS filing 2024 · Most giving: VT, OH, NY | $2K | $2.3M | 74 |
| The Ortner Family Foundation IRS filing 2024 · Most giving: DC, VA, MA | $93.6K | $2.2M | 18 |
| The Oki Foundation IRS filing 2025 · Most giving: WA, CO, GA | $10K | $2.2M | 63 |
| Orr Family Foundation IRS filing 2024 · Most giving: CA, DC, MA | $50K | $2.2M | 28 |
| Orthodox Vision Foundation IRS filing 2024 · Most giving: CA, PA, NY | $5K | $2.2M | 47 |
| The Oaklawn Foundationinc IRS filing 2025 · Most giving: CT, NY, FL | $20K | $2.1M | 117 |
| Onerefugee IRS filing 2025 · Most giving: UT, ID, AZ | $1.3K | $2.1M | 926 |
| Owen D and Jennifer Thomas Family Charitable Foundation IRS filing 2025 · Most giving: NY, VA, DC | $10K | $2.1M | 49 |
| Orentreich Family Foundation IRS filing 2024 · Most giving: NY, NJ, DC | $4.4K | $2.1M | 165 |
| The Orchard Farm Foundation IRS filing 2024 · Most giving: CA, CT, NY | $10K | $2M | 51 |
| Oliver & Jennie Donaldson Char(1071 IRS filing 2024 · Most giving: MA, SC, NY | $26K | $1.8M | 36 |
| Offerdahl Family Foundation IRS filing 2025 · Most giving: ND, NV, DC | $3K | $1.8M | 89 |
| The Orr Family Foundation IRS filing 2024 · Most giving: AZ, TX, NC | $70K | $1.8M | 14 |
| Oritani Charitable Foundation IRS filing 2025 · Most giving: NJ | $50K | $1.8M | 23 |
| The Olseth Foundation IRS filing 2025 · Most giving: MN, OR, DC | $10K | $1.8M | 102 |
| O'Scannlain Family Charitable Foundation IRS filing 2024 · Most giving: MA, IL, NY | $25K | $1.8M | 21 |